Methods and apparatus to assist listeners in distinguishing between electronically generated binaural sound and physical environment sound

ABSTRACT

Methods and apparatus assist listeners in distinguishing between electronically generated binaural sound and physical environment sound while the listener wears a wearable electronic device that provides the binaural sound to the listener. The wearable electronic device generates a visual alert or audio alert when the electronically generated binaural sound occurs.

BACKGROUND

Three-dimensional (3D) sound localization offers people a wealth of newtechnological avenues to not merely communicate with each other but alsoto communicate more efficiently with electronic devices, softwareprograms, and processes.

As this technology develops, challenges will arise with regard to howsound localization integrates into the modern era. Example embodimentsoffer solutions to some of these challenges and assist in providingtechnological advancements in methods and apparatus using 3D soundlocalization.

SUMMARY

Methods and apparatus assist listeners in distinguishing betweenelectronically generated binaural sound and physical environment soundwhile the listener wears a wearable electronic device that provides thebinaural sound to the listener. The wearable electronic device generatesa visual alert or audio alert when the electronically generated binauralsound occurs.

Other example embodiments are discussed herein.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

FIG. 2 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

FIG. 3 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

FIG. 4 is a diagram illustrating how to calculate a location and/ordirection toward a physical environment sound in accordance with anexample embodiment.

FIG. 5 shows an electronic system that provides a listener with an alertto distinguish between physical environment sound and electronicbinaural sound in accordance with an example embodiment.

FIGS. 6A-6H show an electronic system with fields-of-view of a listenerwearing a WED or OHMD during a telephone call or other communicationwith a user in accordance with an example embodiment.

FIGS. 7A-7J show an electronic system with fields-of-view of a listenerwearing a WED or HMD during a telephone call or other communication witha user in accordance with an example embodiment.

FIG. 8 is a method that detects an action of a portable electronicdevice and changes sound in response to detection of the action inaccordance with an example embodiment.

FIG. 9 shows a method that enables a listener to distinguish betweenelectronically generated binaural sound and physical environment soundin accordance with an example embodiment.

FIG. 10 is a computer system or electronic system in accordance with anexample embodiment.

FIG. 11 is a computer system or electronic system in accordance with anexample embodiment.

DETAILED DESCRIPTION

Example embodiments include methods and apparatus that assist listenersin distinguishing between electronically generated binaural sound andphysical environment sound.

An alert provides a person with audio and/or visual information toassist or to enable the person in distinguishing between electronicallygenerated binaural sound and physical environment sound that the personhears. Often, the person simultaneously hears these two types of sounds,hears them in close succession, or hears them mixed together and isunable to distinguish between them. Example embodiments solve theseproblems and other problems discussed herein.

Example embodiments solve other problems with regard to playing orproviding alerts to people so they can distinguish electronicallygenerated binaural sound or binaural audio from physical environmentsound or unaltered naturally occurring sound. For example, consider thefollowing problems: How long should an alert be played or provided tothe person? Where should the alert be played or provided to the person?What type of alert should be played or provided to the person? When intime should the alert be played or provided to the person? How often orfrequently should the alert be played or provided to the person?

By way of introduction, sound localization refers to a person's abilityto determine a location or an origin of sound in direction and distance(though the human auditory system has limits in determining directionand distances to some sounds). Sound localization also refers to methodsto use artificial or computer generated auditory cues to generate anorigin of sound in a virtual 3D space. Binaural sound (or 3D sound) andsome forms of stereo sound provide a listener with the ability tolocalize sound; though binaural sound provides a listener with asuperior ability to localize sounds in 3D space. In many instances, aperson listening to binaural sound through an electronic device (such asearphones or speakers with cross-talk cancellation) can determine alocation from where the sound originates even when this location is awayfrom the person. In some instances, a person listening to binaural soundcan determine both a direction and a distance to an origin of the sound.

Binaural sound has amazing new technological opportunities in augmentedreality (AR), virtual reality (VR), audio augmented reality (AAR),gaming, and telecommunications. For example, when talking to anotherperson over a Voice over Internet Protocol (Vo IP) call, a voice of theother person could appear to originate from a position that is severalfeet in front of the listener. As another example, sounds in a virtualreality (VR) software game can appear to originate at differentlocations around a user in 3D space when the user wears a head mounteddisplay (HMD) or optical head mounted display (OHMD).

One technical challenge is that binaural sound can emulate natural soundfrom the listener's physical environment and in some instances beindistinguishable from natural sound. A listener can be confused orunable to determine whether a sound is an electronically originatingbinaural sound that augments a listener's reality (AR sound) or anaturally occurring binaural sound from the physical environment aroundthe listener, such as a sound from a person, animal, or other naturalsound that occurs within a listener's audible environment. Thisconfusion or inability to distinguish between physical environment (PE)sounds and electronic binaural sounds (e.g., binaural sounds provided toa user through an electronic device) is not desirable in manysituations. Example embodiments solve these technical problems andothers.

The set of sound localization points and the binaural space surroundinga person can function as a three-dimensional audio interface. Some ofthe sounds a listener hears are sounds originating in his physicalenvironment (PE) and are localized with human binaural cues to the pointof the origin of the sound. A listener can also localize other soundshaving binaural cues that are intentionally arranged, or captured fromPE sound originating in another place away from the listener. Soundshaving binaural cues that are not the result of a listener's physicalenvironment can be added to, overlaid on, or augment to his binauralexperience or his audial space as augmented reality (AR) sound. Alistener can localize PE sound and AR sound simultaneously.

In some situations, a listener may need to distinguish soundlocalizations he or she perceives, namely localizations producednaturally in his physical environment (PE) corresponding to soundorigination events occurring in his or her PE, from localizationstriggered by sound augmenting his or her reality (e.g., electronicbinaural sound).

Loudspeakers can produce PE sound that localizes to the position of theloudspeaker. Properly arranged loudspeakers (relative to the position ofa listener) playing binaural sound can produce AR localizations to alistener that do not correspond to the position of a loudspeaker. Alistener in the room with the loudspeakers can hear both PE sound and ARsound. Earphones can provide AR sound. In addition, earphones withmic-through capability can deliver both PE sounds and AR sounds throughthe earphones' drivers without distinction, such that the listener isunable to distinguish between the originations of the sound. Confusionas well as life endangerment can result from a listener's failure todistinguish PE sound from AR sound (aka electronically generatedbinaural sound or electronic binaural sound). Example embodiments solvethese problems and other problems.

People hear human audial cues (for example ITD, ILD, etc.) to determinefor objects in their environment, and the environment itself, positions,sizes, shapes, material composition, surface properties, and more. Byusing binaural sound to present human audial cues, objects, spaces, andtheir properties can be added to a listener's acoustic space. An exampleembodiment provides additional audial cues to AR sound and PE sound thathumans can rely on to efficiently distinguish the AR sound from PEsound.

An example embodiment also provides other methods to distinguish betweenPE sound and AR sound, and methods for a listener to determine if hisaudial reality is being actively augmented, and is capable of beingaugmented.

When a person's audial environment is augmented, it may be achievedthrough ordinary comfortable earphones or headphones, or speakers.Because many types of earphones are comfortable enough to be wornthroughout the day, and while sleeping, a user whose audial environmentis augmented may fail to recall that he is wearing earphones. He may notrecall that earphones are inserted in his ear canals, or that an audialcomponent of an AR system is currently rendering sounds to hisheadphones, earphones, or speakers. Consequently, he may not realizethat the augmented audial information he is hearing inaccuratelycorresponds to events in his physical environment. He may perceive orbelieve that objects, animals, speaking people, weather patterns, etc.,are present with him, when they are not. In addition, he may havetrouble or find himself unable to distinguish between his perceptions ofPE sounds and AR sounds or other electronically generated sounds.

Similarly, a person who is fully aware that his reality is beingaugmented may falsely identify PE sound as AR sound (e.g., someoneknowingly occupying a visually rendered chat space or game, or someonewho has grown accustomed to an acoustically augmented or virtualreality). Both of these phenomena can result in confusion, hazardousscenarios, and danger to the listener or others around him.

In some instances, additional concern is warranted for wearers of customin-ear monitor (CIEM) earphones molded to a wearer's pinnae and/or earcanal(s). These devices can be comfortably worn for extended periods orwhile sleeping. In order to improve the clarity of the sound theydeliver to the wearer, they may have excellent isolation. Howeveracoustic isolation from one's physical environment can be inconvenient,impractical, and dangerous. The complexity of the hazard is compoundedfor a listener who wears CIEMs with outward-facing microphones forbinaural sound capture. An electronic system that has access to the CIEMmicrophones and drivers can allow the wearer to operate them in a“pass-through” or “mic-thru” mode. In the mic-thru mode, sounds from thewearer's environment are captured from microphones and delivered to thedrivers as little as a few millimeters away. The sound can be amplifiedto a level intended to cause the wearer to perceive the sounds of hisphysical environment at the approximate volume of the sound occurring inthe environment. The wearer can be left with an impression that he isnot wearing earphones. A mic-thru feature can be turned on or off,causing his isolation to be active or inactive; and a wearer may notknow the state of the mic-thru feature, or lose track of the state. If awearer believes that he is insulated from PE sound when in fact he isnot, he may falsely identify PE sound as AR sound. If a wearer believesthat he is not insulated from PE sound (that he can hear PE sound) whenin fact his mic-thru is not operating, he can mistake AR sound for PEsound (e.g. he can mistake an insulated experience for a quietenvironment). For example, a listener wearing CIEMs acousticallyisolated from PE sounds can still hear PE sounds via mic-thru. If hismic-thru system fails without his knowledge, he can fail to hear animportant or urgent PE sound without knowing that he has failed to hearit.

Earphones for binaural communication with the convenience of selective(toggleable) isolation may be habitually worn for extended periods dueto their comfort and frequent use throughout the day and/or night. Aconsequent problem exists because confusing or dangerous situations canarise. A listener wearing CIEMs with binaural microphones capable ofoperating in mic-thru mode can be unable to distinguish the manypossible PE sounds (delivered to him binaurally through the earphones)from the many possible externalized binaural sounds (also delivered byhis earphones) not originating in his physical environment.

An electronic system such as a sound localization system (SLS) cananalyze, process, modify, or create sound prior to or as it is played toa listener. The electronic system can monitor or capture mic-thru soundfor processing or modification. The electronic system can thus provideboth PE sound and electronic binaural sound to the listener.

Mic-thru sound can be processed by the system before being delivered foroutput to the listener's earphones. For example, the electronic systemcan amplify the captured PE sound. The electronic system can alsoexecute additional processes to modify the PE sound.

Consider an example in which a smartphone is coupled to earphones withoutward-facing binaural mics, and the smartphone executes software thatsends AR sound to the earphones. The smartphone also executes softwarethat receives captured PE sound from the mics, processes the sound, andplays the sound to the earphones.

FIG. 1 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

Block 100 states convolve, with a processor, a voice of a user withsound localization information (SLI) so the voice of the user externallylocalizes to a listener as electronically generated binaural sound thatis at least three feet away from the listener.

One or more processors and/or electronic devices convolve the voice withsound localization information that includes, but is not limited to, oneor more of head related transfer functions (HRTFs), head related impulseresponses (HRIRs), interaural time differences (ITDs), interaural leveldifferences (ILDs), room impulse responses (RIRs), and binaural roomimpulse responses (BRIRs).

For example, a processor (such as a digital signal processor or DSP) ina server or a handheld portable electronic device (HPED) processes thevoice with SLI (including a pair of HRTFs). The listener hears theprocessed voice through a wearable electronic device, such as a headmounted display (HMD), optical head mounted display (OHMD), electronicglasses, a smartphone attached to a head mounted device, wireless orwired headphones or earphones. The processed voice localizes as binauralsound or 3D sound to the listener at a location that is a far-fielddistance from the listener, such as one meter or more away or three feetor more away from the listener.

By way of example, the sound localization information (SLI) areretrieved, obtained, or received from memory, a database, a file, anelectronic device (such as a server, cloud-based storage, or anotherelectronic device in the computer system or in communication with a PEDproviding the sound to the user through one or more networks), etc. Forinstance, the information includes one or more of HRTFs, ILDs, ITDs,and/or other information discussed herein. Instead of being retrievedfrom memory, this information can also be calculated in real-time.

An example embodiment processes and/or convolves sound with the SLI sothe sound localizes to a particular area or point with respect to auser. The SLI required to process and/or convolve the sound is retrievedor determined based on a location of a desired sound localization pointSLP. For example, if the SLP is to be located one meter in front of aface of the listener and slightly off to a right side of the listener,then an example embodiment retrieves the corresponding HRTFs, ITDs, andILDs and convolves the sound to this location. The location can be morespecific, such as a precise spherical coordinate location of (1.2 m,25°, 15°), and the HRTFs, ITDs, and ILDs are retrieved that correspondto the location. For instance, the retrieved HRTFs have a coordinatelocation that matches or approximates the coordinate location wheresound is desired to originate to the user. Alternatively, the locationis not provided but the SLI is provided (e.g., a software applicationprovides to the DSP HRTFs and other information to convolve the sound).

The SLP can also exist or coincide with a location of an object, avirtual reality (VR) image, or an augmented reality (AR) image. Forexample, a person wears a wearable electronic device that displays an ARor VR image that represents the user with whom the person communicates(e.g., during a telephone call, a VR software game, an AR softwareapplication, etc.). This image has a coordinate location with respect tothe point-of-view of the person wearing the WED, such as having athree-dimensional coordinate location in a VR environment with respectto the person. The wearable electronic device convolves or processes thevoice of the user with HRTFs having coordinate locations that match orapproximate the three-dimensional coordinate location associated withthe image. The listener externally localizes the voice of the user tothe three-dimensional coordinate location where he or she understands orsees the image to be.

A central processing unit (CPU), processor (such as a DSP), ormicroprocessor processes and/or convolves the sound with the SLI, suchas a pair of head related transfer functions (HRTFs), ITDs, and/or ILDsso that the sound will localize to a zone, area, or SLP. For example,the sound localizes to a specific point (e.g., localizing to point (r,θ, ϕ)) or a general location or area (e.g., localizing to far-fieldlocation (θ, ϕ) or near-field location (θ, ϕ)). Additionally, as noted,sound can be convolved or processed to localize to a VR or AR image.

The SLI can be stored in memory in the local electronic device (e.g.,the HPED or wearable electronic device), a remote electronic device(e.g., a server in communication with the HPED or wearable electronicdevice), or another electronic device (e.g., a portable flash storage ora portable electronic device with wireless transmission capabilities).As an example, a lookup table that stores a set of HRTF pairs includes afield/column that specifies the coordinates associated with each pair,and the coordinates indicate the location for the origination of thesound. These coordinates include a distance (r) or near-field orfar-field designation, an azimuth angle (θ), and/or an elevation angle(ϕ).

The complex and unique shape of the human pinnae transforms sound wavesthrough spectral modifications as the sound waves enter the ear. Thesespectral modifications are a function of the position of the source ofsound with respect to the ears along with the physical shape of thepinnae that together cause a unique set of modifications to the soundcalled head related transfer functions or HRTFs. A unique pair of HRTFs(one for the left ear and one for the right ear) can be modeled ormeasured for each position of the source of sound with respect to alistener.

A HRTF is a function of frequency (f) and three spatial variables, byway of example (r, θ, ϕ) in a spherical coordinate system. Here, r isthe radial distance from a recording point where the sound is recordedor a distance from a listening point where the sound is heard to anorigination or generation point of the sound; θ (theta) is the azimuthangle between a forward-facing user at the recording or listening pointand the direction of the origination or generation point of the soundrelative to the user; and ϕ (phi) is the polar angle, elevation, orelevation angle between a forward-facing user at the recording orlistening point and the direction of the origination or generation pointof the sound relative to the user. By way of example, the value of (r)can be a distance (such as a numeric value) from an origin of sound to arecording point (e.g., when the sound is recorded with microphones) or adistance from a SLP to a head of a listener (e.g., when the sound isgenerated with a computer program or otherwise provided to a listener).

When the distance (r) is greater than or equal to about one meter (1 m)as measured from the capture point (e.g., the head of the person) to theorigination point of a sound, the sound attenuates inversely with thedistance. One meter or thereabout defines a practical boundary betweennear-field and far-field distances and corresponding HRTFs. A“near-field” distance is one measured at about one meter or less;whereas a “far-field” distance is one measured at about one meter ormore. Example embodiments are implemented with near-field and far-fielddistances.

The coordinates for external sound localization can be calculated orestimated from an interaural time difference (ITD) of the sound betweentwo ears. ITD is related to the azimuth angle according to, for example,the Woodworth model that provides a frequency independent ray tracingmethodology. The coordinates (r, θ, ϕ) for external sound localizationcan also be calculated from a measurement of an orientation of and adistance to the face of the person when a head related impulse response(HRIR) is captured.

The coordinates can also be calculated or extracted from one or moreHRTF data files, for example by parsing known HRTF file formats, and/orHRTF file information. For example, HRTF data is stored as a set ofangles that are provided in a file or header of a file (or in anotherpredetermined or known location of a file or computer readable medium).The data can include one or more of time domain impulse responses (FIRfilter coefficients), filter feedback coefficients, and an ITD value.This information can also be referred to as “a” and “b” coefficients. Byway of example, these coefficients are stored or ordered according tolowest azimuth to highest azimuth for different elevation angles. TheHRTF file can also include other information, such as the sampling rate,the number of elevation angles, the number of HRTFs stored, ITDs, a listof the elevation and azimuth angles, a unique identification for theHRTF pair, and other information. The data can be arranged according toone or more standard or proprietary file formats, such as AES69, andextracted from the file.

The coordinates and other HRTF information are calculated or extractedfrom the HRTF data files. A unique set of HRTF information (including r,θ, ϕ) is determined for each unique HRTF.

The coordinates and other HRTF information are also stored in andretrieved from memory, such as storing the information in a look-uptable or other memory discussed herein. The information is quicklyretrieved to enable real-time processing and convolving of sound usingHRTFs and hence improves computer performance of execution of binauralsound.

The SLP represents a location where a person will perceive an origin ofthe sound. For an external localization, the SLP is away from the person(e.g., the SLP is away from but proximate to the person or away from butnot proximate to the person). Further, this SLP can be located at aphysical or tangible object (such as located at a chair or picture on awall) or located in empty space or empty virtual space. The empty spacecan be void of an image (e.g., empty space located in front of a face ofa listener) or included with an image (e.g., located in a VR environmentthat includes an image, such as at a VR object). The SLP can also belocated inside the head of the person (e.g., when the sound is providedas mono sound or stereo sound).

A location of the SLP corresponds to the coordinates of one or morepairs of HRTFs, or corresponds to a coordinate location or zone where alistener perceives a localization due to the influence of a visual cue(e.g., an image, object, or device), or a known or understood locationthat is not visible (e.g., a recently witnessed or anticipated locationof a SLP, a device that is out of a field-of-view, an avatar suddenlyoccluded by another virtual object).

For example, the coordinates of or within a SLP or a zone match orapproximate the coordinates of a HRTF. Consider an example in which thecoordinates for a pair of HRTFs are (r, θ, ϕ) and are provided as (1.2meters, 35°, 10°). A corresponding SLP or zone intended for a personthus includes (r, θ, ϕ), provided as (1.2 meters, 35°, 10°). In otherwords, the person will localize the sound as occurring 1.2 meters fromhis or her face at an azimuth angle of 35° and at an elevation angle of10° taken with respect to a forward-looking direction of the person. Inthe example, the coordinates of the SLP and HRTF match.

As another example, a listener perceives a SLP or sound from a soundsource at a near-field physical object, and the HRTFs convolving theperceived sound have far-field coordinates along the line-of-sight fromthe head of the listener to the object. In this case, one or more of theSLP coordinates do not match the coordinates of the object (e.g., the rcoordinates do not match). HRTF pairs having coordinates matching thecoordinates of the object may be unavailable to the listener. Later asthe listener localizes the sound to the object, a barrier is placed suchthat the listener is blocked from seeing the object. The listenercontinues to localize the sound to the object, with the object as theSLP because the listener remains aware that the object has not moved.

SLI can also be approximated or interpolated based on known data orknown SLI, such as SLI for other coordinate locations. For example, aSLP is desired to localize at coordinate location (2.0 m, 0°, 40°), butHRTFs for the location are not known. HRTFs are known for twoneighboring locations, such as known for (2.0 m, 0°, 35°) and (2.0 m,0°, 45°), and the HRTFs for the desired location of (2.0 m, 0°, 40°) areapproximated from the two known locations. These approximated HRTFs areprovided to convolve sound to localize at the desired coordinatelocation (2.0 m, 0°, 40°).

Sound is convolved either directly in the time domain with a finiteimpulse response (FIR) filter or with a Fast Fourier Transform (FFT).For example, an electronic device convolves the sound to one or moreSLPs using a set of HRTFs, HRIRs, BRIRs, or RIRs and provides the personwith binaural sound.

In an example embodiment, convolution involves an audio input signal andone or more impulse responses of a sound originating from variouspositions with respect to the listener. The input signal is a limitedlength audio signal (such as a pre-recorded digital audio file) or anongoing audio signal (such as sound from a microphone or streaming audioover the Internet from a continuous source). The impulse responses are aset of HRIRs, BRIRs, RIRs, etc.

Convolution applies one or more FIR filters to the input signals andconvolves the input signals into binaural audio output or binauralstereo tracks. For example, the input signals are convolved intobinaural audio output that is specific or individualized for thelistener based on one or more of the impulse responses to the listener.

The FIR filters are derived binaural impulse responses that are executedwith example embodiments discussed herein (e.g., derived from signalsreceived through microphones placed in, at, or near the left and rightear channel entrance of the person). Alternatively or additionally, theFIR filters are obtained from another source, such as generated from acomputer simulation or estimation, generated from a dummy head,retrieved from storage, etc. Further, convolution of an input signalinto binaural output can include sound with one or more ofreverberation, single echoes, frequency coloring, and spatialimpression.

Processing of the sound also includes calculating and/or adjusting aninteraural time difference (ITD), an interaural level difference (ILD),and/or other aspects of the sound in order to alter the cues andartificially alter the point of localization. Consider an example inwhich the ITD is calculated for a location (θ, ϕ) with discrete Fouriertransforms (DFTs) calculated for the left and right ears. The ITD islocated at the point for which the function attains its maximum value,known as the argument of the maximum or arg max as follows:

${ITD} = {\arg\max(\tau){\sum\limits_{n}{{d_{i,\theta,\phi}(n)} \cdot {{d_{r,\theta,\phi}\left( {n + \tau} \right)}.}}}}$

Subsequent sounds are filtered with the left HRTF, right HRTF, and/orITD so that the sound localizes at (r, θ, ϕ)). Such sounds includefiltering stereo and monaural sound to localize at (r, θ, ϕ)). Forexample, given an input signal as a monaural sound signal s(n), thissound is convolved to appear at (θ, ϕ) when the left ear is presentedwith:s _(l)(n)=s(n−ITD)·d _(l,θ,ϕ)(n);and the right ear is presented with:s _(r)(n)=s(n)·d _(r,θ,ϕ)(n).

Consider an example in which a dedicated digital signal processor (DSP)executes frequency domain processing to generate real-time convolutionof monophonic sound to binaural sound.

By way of example, a continuous audio input signal x(t) is convolvedwith a linear filter of an impulse response h(t) to generate an outputsignal y(t) as follows:

${y(\tau)} = {{{x(\tau)} \cdot {h(\tau)}} = {\overset{\infty}{\int\limits_{0}}{{x\left( {\tau - t} \right)} \cdot {h(t)} \cdot {{dt}.}}}}$

This reduces to a summation when the impulse response has a given lengthN and the input signal and the impulse response are sampled at t=iDt asfollows:

${y(i)} = {\sum\limits_{j = 0}^{N - 1}{{x\left( {i - j} \right)} \cdot {{h(j)}.}}}$

Execution time of convolution further reduces with a Fast FourierTransform (FFT) algorithm and/or Inverse Fast Fourier Transform (IFFT)algorithm.

Consider another example of binaural synthesis in which recorded orsynthesized sound is filtered with a binaural impulse response (e.g.,HRIR or BRIR) to generate a binaural output sound to the person. Theinput sound is preprocessed to generate left and right audio streamsthat are mapped to one or more sound localization points (known asSLPs). These streams are convolved with a binaural impulse response forthe left ear and the right ear to generate the left and right binauraloutput sound signal. The output sound signal is further processeddepending on a final destination. For example, a cross-talk cancellationalgorithm is applied to the output sound signal when it will be providedthrough loudspeakers or applying artificial binaural reverberation toprovide 3D spatial context to the sound.

Example embodiments designate or include an object, image, point, ordevice on the ray that extends from a head of a listener to the intendedSLP (such as displaying an image as or in line with the intended SLP).For an external localization, the SLP is away from the person (e.g., theSLP is away from but proximate to the person or away from but notproximate to the person). The SLP can also be located inside the head ofthe person (e.g., when sound is provided to the listener in stereo ormono sound).

Block 110 states provide, with a wearable electronic device, the voiceof the user as the electronically generated binaural sound thatexternally localizes to the listener.

Binaural sound is provided to the listener through one or moreelectronic devices including, but not limited to, one or more of boneconduction headphones, speakers of a wearable electronic device (e.g.,headphones, earphones, electronic glasses, earbuds, head mounteddisplay, smartphone, etc.). Binaural sound can be processed forcrosstalk cancellation and provided through other types of speakers(e.g., dipole stereo speakers).

From the point-of-view of the listener, the sound originates or emanatesfrom the object, point, area, or location that corresponds with the SLP.For example, an example embodiment selects an intended SLP at, on, ornear a physical object, a VR object, or an AR object (includinglocations behind the object). When the sound is convolved with HRTFscorresponding to the intended SLP (including HRTFs behind the intendedSLP), then the sound appears to originate to the listener at the object.

When binaural sound is provided to the listener, the listener will hearthe sound as if it originates from the SLP (e.g., a VR image or ARimage). The sound, however, does not originate from the SLP since theSLP may be at an inanimate object with no electronics or an animateobject with no electronics. For example, the SLP is an empty point inspace approximately one meter away from the head of the listener.Alternatively, the SLP is designated at an object that has electronicsbut does not have the capability to generate sound (e.g., the SLP has nospeakers or sound system). As yet another example, the object at a SLPhas speakers and the ability to provide sound but is not providing soundto the listener. In each of these examples, the listener perceives thesound to originate from the object, but the object does not produce thesound. Instead, the sound is altered or convolved and provided to thelistener so the sound appears to originate from the object.

Sound localization information (SLI) is stored and categorized invarious formats. For example, tables or lookup tables store SLI forquick access and provide convolution instructions for sound. Informationstored in tables expedites retrieval of stored information, reduces CPUtime required for sound convolution, and reduces a number of instructioncycles. Storing SLI in tables also expedites and/or assists inprefetching, preprocessing, caching, and executing other exampleembodiments discussed herein. SLI can be stored in read only memory(ROM) or random access memory (RAM) of an electronic device thatincludes or does not include a table.

Consider an example in which a HPED determines an identity of a listener(e.g., with a biometric sensor such as one discussed herein) andretrieves HRTFs associated with the identified listener. These HRTFs arepersonalized or unique to the listener since every individual has aunique or special set of left and right HRTFs for a given coordinatelocation with respect to a head orientation of the individual. Forexample, a listener logs in to a computer system or electronic device,and the computer system or electronic device retrieves from memory HRTFsunique to the identity of the listener. As another example, the listenerspeaks at the outset of a phone call, or in issuing a voice command toestablish a voice communication, an electronic device or process in thecomputer system processes the voice in order to determine a voiceprintor voice-id of the listener. The voiceprint is used to lookup andspecify or retrieve a HRTF set for the listener. As another example, aHPED captures, with a camera in the HPED, the face of a first userduring telephony with a second user. Facial recognition softwareanalyzes the facial image of the first user to determine his or heridentity. Memory stores HRTFs for different users (e.g., personalizedHRTFs or preferred HRTFs). Based on the identity of the user, the HPEDretrieves far-field HRTFs that are assigned to the first user. Aprocessor in the HPED or a process in a server in communication with theHPED convolves the voice of the second user with the selected far-fieldHRTFs.

Consider an example in which a telephony service or telecommunicationprovider stores thousands or millions of left and right HRTF pairs orHRTF sets that are each associated with many characteristics of a personor model from whom they were measured or calculated. In addition, eachHRTF set is associated with many characteristics of one or more usersfor whom the HRTFs provide a high level of realism. The manycharacteristics can include aspects of a face captured from a camera(e.g., aspects used in the execution of facial recognition), aspects ofa voice (such as aspects of voice that are assessed in voiceidentification), a height, weight, gender, race, age, ear shape, eyecolor, hairstyle, hair type, chest size, type of clothing (e.g., thicksweater or sheer blouse), type of sound that was, will be, or is oftenconvolved for the person, and other data and biometrics. Taken together,these data are used to predict for a particular listener which of thelarge multiplicity of HRTFs stored by the service or provider in thecloud or memory are most likely to provide a high level of realism tothe listener. A selection of an HRTF set based on the prediction isprovided to an electronic device of the listener or otherwise executedto convolve sound for the listener. A level of satisfaction or realismis determined during the playing of the sound, and the determined levelis used to adjust future predictions of HRTFs for the listener and otherlisteners.

Block 120 states provide, with a wearable electronic device, an alertthat signifies to the listener that the electronically generatedbinaural sound is the voice of the user to enable the listener todistinguish between the electronically generated binaural sound andphysical environment sound.

The alert includes one or more of visual alerts (e.g., alerts that thelistener can see) and/or audio alerts (e.g., alerts that the listenercan hear). The alert enables the listener to distinguish between hearingelectronically generated binaural sounds and physical environmentsounds. The alert can also be a tactile alert, such as a vibration orhaptic feedback. For example, a listener configures a wrist-phone toring at a SLP that is two meters away. There are many people withwrist-phones and HPEDs in the room with the listener. An exampleembodiment vibrates the wrist-phone of the listener during the playingof the binaural ringtone. This alerts the listener that the externalizedsound of a ringing phone in the room two meters away is the wrist-phoneof the listener.

Consider an example embodiment that generates an audible alert thatincludes, but is not limited to, one or more of a tone, a beep, a bang,a buzz, a voice, music, or a sound effect or audio effect. The audiblealert also includes a recognizable audio tweak or sound, such as soundbeing played to the listener at a particular pitch, frequency, timbre,reverberation, word pace, syllabic tempo, play rate, resonance, color,spectral profile, or other qualities of a sound and their combinations.

Consider an example embodiment that generates a visual alert thatincludes, but is not limited to, one or more of flashing a light,providing a constant light, dimming a light (e.g., on an object orbackground), brightening a light (e.g., an object or background),providing a certain color light (e.g., providing a blue or green lighton an object), displaying an object or animation, removing an object oranimation, spinning or rotating an object or animation, moving an objector animation, changing a color of an object or background, adding orremoving animation, speeding or slowing an animation, pausing orresuming an animation, enlarging a size of an object or animation, andreducing a size of an object or animation.

An example embodiment provides the alert at one or more of the followingtimes: (1) when or before the electronically generated binaural soundcommences or begins to play to the listener (e.g., at a point in timeright before or when the listener hears the electronically generatedbinaural sound), (2) when the electronically generated binaural soundfinishes or stops playing to the listener, (3) when the physicalenvironment sound commences or begins to the listener (e.g., at a pointin time when the listener begins to hear the physical environmentsound), (4) when the physical environment sound finishes or stops to thelistener, (5) while the electronically generated binaural sound plays tothe listener, and (6) while the physical environment sound plays to thelistener.

The duration of the alert can be short (e.g., less than a second) orlonger (e.g., longer than a second). Further, the duration of time thatthe alert is provided to the listener can be based on an amount of timeof the electronically generated binaural sound and/or physicalenvironment sound. For example, provide the alert to the listener duringor while the electronically generated binaural sound plays to thelistener. As another example, provide the alert to the listener duringor while the physical environment sound is present or exists. The volumeof an audible alert can be low or high relative to the sound triggeringthe alert or relative to other sound (e.g., softer or louder than thesound triggering the alert, softer or louder than other sound playing,softer or louder than recent PE sounds, softer or louder than predictedPE or AR sound, softer or louder than average PE or AR sound). Thevolume and/or duration of an auditory alert, and the brightness, colorand/or duration of a visual alert can correspond to the loudness of thesound that triggers the alert. For example, a bright red visual alertcan correspond to a loud PE sound; a long auditory alert can correspondto a loud AR sound.

Example embodiments can be applied to hardware, software, and electronicdevices that provide electronically generated binaural sound or 3D soundto listeners. By way of example, these applications include, but are notlimited to, telephone calls or telephony, VR games and VR softwareapplications (e.g., games and software applications that execute with aHMD or a smartphone being worn as a HMD), and AR games and AR softwareapplications (e.g., games and software applications that execute withelectronic glasses or a smartphone being worn on a head of a person).

FIG. 2 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

Block 200 states detect, while a listener wears a wearable electronicdevice, physical environment sound and/or electronically generatedbinaural sound.

The wearable electronic device monitors for the existence of physicalenvironment sound and/or electronically generated binaural sound.

For example, the wearable electronic device (or another electronicdevice in communication with the wearable electronic device) includesone or more sensors that detect the presence of the sound or thepresence of a person or object that can make the sound. By way ofexample, these sensors include, but are not limited to, one or more of asingle microphone, multiple microphones, a camera, a proximity sensor,radio frequency identification (RFID) sensor, motion sensor or motiondetector, and a sound detector or sound sensor.

Electronically generated binaural sound does not necessarily have to bedetected with a sensor since this sound can be electronically generatedand wirelessly transmitted (e.g., generated with hardware and/orsoftware). For example, a VR software application executing on awearable electronic device generates 3D sound and provides this sound tothe listener. This software application knows when in time this sound isor will be provided to the listener. As another example, the wearableelectronic device includes a wireless transmitter and receiver thattransmit and receive sounds or voice during a telephone call over theinternet or other network. The wearable electronic device knows when intime this sound is being played via the wireless receiver during thetelephone call.

Block 210 makes a determination as to whether the sound is detected.

If the answer to block 210 is “no” flow proceeds back to block 200.

If the answer to block 210 is “yes” flow proceeds to block 220 thatstates provide a visual and/or audio alert to the listener of thephysical environment sound and/or electronically generated binauralsound, or take another action.

For example, other actions include, but are not limited to, one or moreof the following: silence music of video player software applicationwhen a AR sound is detected, mute AR sound when a loud PE sound isdetected, or when PE changes suddenly such as an unexpected oruncharacteristic silence, incrementing a timer or resetting a timer thattracks a duration of a sound or lack of sound in order to monitorthresholds of AR sound or PE sound activity, and other actions.

When the wearable electronic device detects physical environment soundand/or electronically generated binaural sound, the wearable electronicdevice initiates a visual and/or audio alert to the listener wearing thewearable electronic device. The alert can initiate or activate upondetecting the physical environment sound, detecting the electronicallygenerated binaural sound, detecting both, or detecting neither.

FIG. 3 is a method that provides an alert to a listener to enable thelistener to distinguish between electronically generated binaural soundand physical environment sound in accordance with an example embodiment.

Block 300 states detect, while a listener wears a wearable electronicdevice, physical environment sound.

In an example embodiment, one or more sensors monitor and/or detect thephysical environment sound. For example, this sound originates from aperson or object that is proximate or near the listener while thelistener wears the wearable electronic device. For example, the physicalenvironment sound originates from a person or object in a same room ofthe listener, within an audible range of the listener, or within a rangethat is detectable by microphones.

Block 310 states determine, based on the detection of the physicalenvironment sound, a location and/or direction of the physicalenvironment sound.

The location and/or direction of the physical environment sound can becalculated from sound waves received at one or more sensors of thewearable electronic device, such as a microphone in or at a left ear ofthe listener and a microphone in or at the right ear of the listener.

Block 320 states provide, with the wearable electronic device, thevisual and/or audio alert to a location based on the detected locationand/or direction of the physical environment sound.

The visual and/or audio alert is provided to the listener at thelocation and/or direction toward the physical environment sound so thelistener can visually and/or audibly determine this location and/ordirection from the alert (as opposed to determining the location and/ordirection from the physical environment sound itself). For example, theearphones or speakers included with a HMD have binaural microphones tomonitor PE sound but do not have a pass-thru mode. As another example,in order to concentrate on a VR task the listener has activated anactive noise control (ANC) feature and de-activated the pass-thru mode.As another example, even though the listener may hear the physicalenvironment sound, the listener may be preoccupied with sights and/orsounds from the wearable electronic device and thus unable to determinethe location and/or direction of the physical environment sound. Asanother example a passenger wears an HMD while underway in an automobileand has no reason to listen to PE sound inside the automobile or outsidethe automobile. However, for the sake of safety, the passenger allowsthe microphones of the HMD to monitor the sound inside and/or outsidethe auto and to provide a visual or auditory alert for important and/orloud PE sounds. As still another example, a player engrossed in a gameexecuting on a HPED wears CIEMs that provide excellent acousticisolation such that the player cannot hear PE sound in the frequencyrange of human speech. An example embodiment executes on the HPED tomonitor the PE sound and to display the direction toward PE soundsources that fall within the frequency range of human speech. When humanspeech PE sound is detected, the example embodiment briefly flashes thedisplay of the HPED and displays an arrow indicating a direction of aspeaking person. An increasing number of people wear earphones for longperiods in order to occupy an alternative or virtual auditoryenvironment. These many examples emphasize a growing need for solutionsthat provide protection and improve safety for a society that isincreasingly straddling virtual and physical environments. Exampleembodiments provide a vast improvement in safety for electronic devicesand software executing binaural sound.

An example embodiment provides or displays the alert at a coordinatelocation that corresponds to the coordinate location of the sensedphysical environment sound with the microphones. This alert can beprovided as electronically generated binaural sound and/or a visualalert.

Consider an example in which the listener wears a HMD while interactingwith a VR software application or game (e.g., the listener communicateswith an image representing a user in a telephone call or other type ofcommunication). Two microphones at the ears of the listener detect avoice of a person in the environment of the user (the voice being thephysical environment sound). This voice occurs at an azimuth directionof forty-five degrees (45°) with respect to the current forward-facinghead orientation of the listener. The HMD displays an image representingthe talking person in the VR world of the listener at the same orsimilar location of the actual voice of the person with respect to thelistener. Thus, the image representing the talking person appears to thelistener at forty-five degrees (45°) azimuth. As such, even though thelistener cannot see the person, the listener knows the relative locationof the person with respect to the direction that his or her head ispointing.

Sound can also be convolved to localize to match, equal, or correspondto the location of the physical environment sound. In the example abovewith the HMD, a processor convolves an audible alert with HRTFs havingcoordinates (r>1.0 m, 45°, 0°). Convolution with these HRTFs places theaudible alert at the location of the image that represents the person inthe physical environment of the listener.

Consider an example of a hearing-impaired person who dons smart glassesin order to monitor the direction of origin of loud people, audiblehazards, or important auditory events in the physical environment thatare not visible. An example embodiment alerts the wearer to the presenceof and locations of these sound sources in the physical environment withvisual alerts corresponding to the direction(s) of the source(s) of thesound. Another type of alert that can be used to notify the listener orwearer is a tactile or vibration alert. The example embodiment alsoincludes tactile feedback that reinforces indication of a presence ofand directions toward active PE sound sources in the form a headbandincluded with the smart glasses that looks like a headband of a tennisplayer. The headband includes an array of vibrating motors around thecircumference. The example embodiment actuates one or more vibratingmotors corresponding to the direction of the PE sound sources at a speedor effective pressure corresponding to the loudness of each PE soundsource. This allows the hearing-impaired wearer to be alerted to thedirection of a loud noise coming from 45° azimuth by seeing an imagedisplayed in his or her FOV at 45° azimuth and feeling a vibration alongthe headband at a matching azimuth (e.g., on the surface of his or herforehead, midway between the median plane and the right ear).

FIG. 4 is a diagram illustrating how to calculate a location and/ordirection of a physical environment sound in accordance with an exampleembodiment.

For illustration, a source of sound 400 emits a sound that is receivedat two spaced microphones 410 and 420. The source of sound (being thephysical environment sound) is a distance (r1) from microphone 410 and adistance (r2) from microphone 420. Furthermore, microphone 410 senses asound pressure (p1) and sound intensity (l1); and microphone 420 sensesa sound pressure (p2) and sound intensity (l2).

Sound pressure (p) decreases inversely proportionate to the distance (r)from the measuring point to the source of the sound (i.e., 1/r from themeasuring point to the source of the sound). When the distance (r)doubles, the sound pressure measured at the measuring point decreases byone half (½) of the value at the source of the sound.

Sound intensity (I) decreases inversely proportionate to the squareddistance from the measuring point to the source of the sound (i.e.,1/r²). When the distance (r) doubles, the sound intensity measured atthe measuring point decreases by one quarter (¼) of the value at thesource of the sound.

Furthermore, sound level (SPL) of a sound wave generally decreases by 6decibels (dB) at double the distance from the source of the sound.

Sound pressure can be written according to distance as follows:

${r2} = {r1\frac{p1}{p2}}$

Sound intensity can be written according to distance as follows:

${r2} = {r1\sqrt{\frac{I1}{I2}}}$

Furthermore, the sound level (L) in decibels can be calculated at eachof the microphones as L1 at microphone 410 and L2 at microphone 420 asfollows:

${L2} = {{L1} - {❘{20\log\left( \frac{r1}{r2} \right)}❘}}$

By way of example, two microphones positioned at the ears of thelistener measure sound pressure of the incoming physical environmentsound. Time difference of arrival (TDOA) can be calculated to determinea direction of the source of the physical environment sound. Forexample, a cross-correlation function between the two microphonesdefines a level of correlation between output of the two microphones.For instance, interaural time difference (ITD) is provided as thedifference in arrival time of the sound between the two microphonesoccurs as follows:

${\Delta t} = \frac{x\sin\theta}{c}$

where Δt is the time difference in seconds; x is the distance betweenthe microphones; and θ is the angle between the baseline of themicrophones and the incident sound.

The calculations TDOA or ITD can be compensated for differences in timedue to sound travel around or partially around a head of the listener.Furthermore, ITDs can be extracted or obtained from previousmeasurements, such as stored HRTF data. The measured or recorded ITDs onthe listener are compared with stored ITDs from HRTF data to obtain theazimuth angle of the origin of the sound source.

In an example embodiment, the location of the alert being presented tothe listener provides directional or locational information. Based onthe information of the alert, the listener can discern a direction ofthe physical environment sound or a location of the physical environmentsound while wearing the wearable electronic device. For example, twomicrophones can determine a direction of a sound source based ondifferent arrival times of the sound at each of the two microphones. Forinstance, determine the time delay between the arrival of the sound ateach microphone and then calculate, using trigonometry, an anglecorresponding to the point of origin of the sound. This calculation ispossible when the distance between the two microphones is known sincethe speed of sound is also known. Next, select a HRTF pair having acoordinate location corresponding to the angle calculated for the pointof origin of the sound. Alternatively or additionally, display a visualalert on a display with a coordinate location that corresponds to theangle calculated for the point of origin.

Consider an example embodiment that enables a listener to distinguishbetween electronically generated binaural sounds and physicalenvironment sounds while a wearable electronic device executes asoftware application, such as a telephone call, VR software application,or AR software application. The listener wears the wearable electronicdevice that communicates with a user (such as another person or asoftware program). A processor (such as a processor in the wearableelectronic device or a processor in wireless communication with thewearable electronic device) processes or convolves the voice of the userwith sound localization information (such as head related transferfunctions or HRTFs). For example, convolution of the voice changes thevoice from stereo or mono sound to binaural sound. Alternatively,convolution of the voice creates the voice as binaural sound (as opposedto changing the voice from mono or stereo to binaural).

This convolved or processed sound externally localizes as theelectronically generated binaural sound to the listener. For example,the voice externally localizes to an AR image, a VR image, a physicalobject, or a location in empty space (with or without an image).Depending on the SLI selected for convolution, the voice externallylocalizes at a near-field distance from the listener (e.g., less thanone meter from the head of the listener) or at a far-field distance fromthe listener (e.g., more than three feet or one meter from the head ofthe listener).

The wearable electronic device or another electronic device provides thevoice to the listener. For example, the wearable electronic devicewirelessly transmits the convolved voice to wireless earphones orwireless headphones that the listener wears. As another example, thewearable electronic device includes speakers at the left and right earsof the listener that provide the voice to the listener. For instance,such speakers form part of a HMD, electronic glasses, or apparatus thatremovably houses a smartphone.

The wearable electronic device detects the electronically generatedbinaural sound or physical environment sound and generates an alert.This alert notifies the listener of the existence, presence, and/orcommencement of the electronically generated binaural sound or physicalenvironment sound. Upon hearing and/or seeing the alert, the listener isable to distinguish between the electronically generated binaural soundsand the physical environment sounds. Without such an alert, the listenermay not be able to distinguish or discern which sounds areelectronically generated binaural sound and which sounds are physicalenvironment sound.

If the alert includes sound, the alert can be provided as one ofdifferent types of sound, such as mono sound, stereo sound, or binauralsound. Mono and stereo sound internally localize inside the head of thelistener, whereas binaural sound externally localizes outside the headof the listener (e.g., externally localizing to a sound localizationpoint or SLP).

Consider an example embodiment that provides the alert as binauralsound. A processor convolves the sound with the SLI (such as HRTFs) ofthe listener so the sound externally localizes. The location of thislocalization can coexist with the location of an image. For example, thelistener talks with a user during a telephone call while wearing a headmounted display. The head mounted display displays an image thatrepresents the user, and a processor convolves or processes the voice ofthe user with the SLI to externally localize at a SLP that matches thelocation of the image. This processor also convolves the alert with theSLI so the alert also externally localizes at a location thatcorresponds to the location of the image and the SLP of the voice of theuser.

The alert can be part of the voice that the listener hears. Consider anexample embodiment that provides the alert as binaural sound. Forexample, the listener talks with a user during a telephone call whilewearing a head mounted display. The head mounted display displays animage that represents the user, and a processor convolves or processesthe voice of the user with the SLI to externally localize at thelocation of the image. This processor adjusts or changes the voice toindicate an alert. The voice continues to externally localize at theimage, but the voice is modified. This modification alerts the listenerthat the wearable electronic device detected a physical environmentsound. For instance, this modification includes, but is not limited to,changing or modifying one or more of pitch or frequency of the voice,timbre or tone of the voice, loudness or amplification of the voice,gender of the voice, identity of the voice (e.g., substituting adifferent voice for the current voice), pausing or stopping the voice,muting the voice, or changing the voice in another audibly perceivableway.

An example embodiment provides a single alert or multiple alerts. Forexample, the alert is repeated at periodic or regularly-spaced timeintervals (e.g., once every second, two seconds, five seconds, tenseconds, fifteen seconds, thirty seconds, minute, two minutes, fiveminutes, ten minutes, etc.). Alternatively, the alert generates atrandom time intervals.

Consider an example in which the wearable electronic device includes oris in communication with one or more microphones. For instance, earbuds,earphones, or headphones include a microphone positioned in or at theleft and right ears. The microphones detect sound, such as a voice of aperson. When the microphones detect a voice, the wearable electronicdevice generates an alert signal that actuates or triggers the alert tothe listener.

Consider an example in which a listener talks to and communicates with auser while wearing a wearable electronic device. The wearable electronicdevice generates an audio alert and/or visual alert to the listener atone or more of the following times: at a point in time when the userstops talking to the listener, at a point in time when the user pausestalking to the listener, at a point in time when the user starts talkingto the listener, while the user talks to the listener, and while theuser does not talk to the listener.

Consider an example in which a wearable electronic device includesspeakers that are positioned at or in the ears of the listener wearingthe wearable electronic device. These speakers produce an audio alert inone of mono sound or stereo sound at a point or points in time while thevoice of the user externally localizes to the listener as binauralsound. Alternatively or additionally, the speakers produce an audioalert to the listener as a background sound during the time when theuser is talking to the listener (e.g., during a telephone call or verbalcommunication between the listener and the user). For example, thebackground sound is music, an environmental sound such as running water,rain, waves, birds, a breeze, an ambience (e.g., a murmur of voices ofpatrons at a café, distant traffic or machinery), or a room tone (e.g.,within a jumbo jet fuselage, a quiet office, a snowy field, an ambienceconvolved with a particular BRIR or RIR) or a voice of a personinstructing the listener of the alert.

Consider an example embodiment that enables a listener to distinguishbetween a voice of a user that is electronically generated binauralsound and a voice emanating from a person in a physical environmentwhere the listener is located. The listener communicates with a user andwears a wearable electronic device that displays an image thatrepresents the user. For example, this image includes, but is notlimited to, one of a real-time picture or photo of the user, a real-timevideo of the user, a still or moving animated image of the user, a stillor moving animated image of someone or something other than the user(e.g., an image of a talking rabbit when the user is a real person), anavatar, a cartoon character, an object that the user selected torepresent himself/herself/itself. Further, such images include 2Dimages, 3D images, AR images, and VR images.

A processor in the wearable electronic device or in communication withthe wearable electronic device processes the voice of the user withHRTFs so the voice of the user externally localizes as electronicallygenerated binaural sound to empty space that is at least one meter orthree feet away from the listener (e.g., convolving the voice withfar-field HRTFs). Left and right speakers (located at the ears of thelistener) provide the voice to the listener as the electronicallygenerated binaural sound. One or more microphones (such as microphoneslocated at the ears of the listener in the wearable electronic device)capture a voice of a person near or proximate to the listener while thelistener wears the wearable electronic device and communicates with theuser. In response to capturing this sound with the microphones, thewearable electronic device generates an audible and/or visual alert tothe listener. The alert notifies the listener that the sound he or sheis hearing is not electronically generated binaural sound, but physicalenvironment sound.

Consider an example in which the wearable electronic device displays avisual alert that activates while the user is speaking to the listenerduring the telephone call to enable the listener to distinguish betweenthe voice of the user and the voice emanating from the person in thephysical environment where the listener is located. The visual alertremains activated (e.g., remains illuminated) while the microphonescontinue to detect that the person in the physical environment isspeaking. The visual alert deactivates (e.g., turns off) when themicrophones stop detecting or fail to detect that the person in thephysical environment is speaking.

Consider an example in which the wearable electronic device displays avisual alert as a colored light while the user is speaking to thelistener. The light provides the listener with a visual indication whenthe user is talking. For example, the light includes one of a bluecolor, a red color, a yellow color, a green color, or another color.Illumination of the light provides the listener with a visual indicationthat the sound he or she is hearing originates from the physicalenvironment and not from the wearable electronic device. For instance,the light continuously remains on or illuminated or repeatedly flasheswhile the user speaks.

Consider an example in which the listener wears a wearable electronicdevice that displays an image of a user while the listener communicatesor talks to the user. When another party not involved in thecommunication (e.g., a person in the physical environment of thelistener) talks to the listener, the image of the user flashes or dimsin brightness. This visual alert indicates to the listener that a personnot participating in the communication is speaking to the listener.Additionally, when the other party not involved in the communicationtalks to the listener, the voice attributed to the image of the userbecomes softer or less loud. Reducing a volume of the voicecorresponding to the image of the user enables the listener to betterhear the other party and notifies the listener that the other party istalking to the listener.

Consider an example in which the light changes color when the userspeaks to the listener. For instance, when the user speaks, the lightilluminates green. When the user stops speaking, the light turns off orilluminates red. Alternatively, the light can change brightness orintensity. When the user speaks, the light brightens. When the userstops speaking, the light turns off or dims.

The visual alert can also be a stationary or moving object or virtualobject. For example, the object rotates, spins, or moves through 2D or3D space while being displayed with a wearable electronic device.

Consider an example in which a listener wears a wearable electronicdevice while communicating with a user (e.g., while the electronicdevice executes a telephone call, AR software application, or VRsoftware application). During the communication exchange between thelistener and user, the wearable electronic device displays an image ofthe user as an animated, talking person. The wearable electronic devicedisplays a visual alert as a three-dimensional (3D) image that is in afield-of-view of the listener but that is not located at the image thatrepresents the user. When the user speaks, a mouth of the image of theuser moves to emulate a speaking person. At the same time, the 3D imagerotates while the user speaks to provide a second visual indication thatthe sound being provided to the listener is electronically generatedbinaural sound. When the user stops talking, the 3D image stops rotatingto visually indicate to the listener that the user is no longer speakingto the listener.

In an alternate embodiment, the visual alert does not activate when theuser speaks, but instead activates when the wearable electronic devicedetects a sound, noise, gesture, or voice from the physical environmentwhere the listener is located.

Consider the example above in which the listener communicates with theuser while the listener wears a wearable electronic device. A person ina room with the listener speaks to the listener while the listener talksto the user. Without a visual and/or audio warning, the listener will beconfused as to the origin of the voice of the person. Is the personlocated with the user or did the voice originate at the location of thelistener?

In order to solve this problem, the wearable electronic device activatesthe alert upon detecting the voice of the person in the room with thelistener. The wearable electronic device includes a sensor (e.g., amotion sensor, proximity sensor, microphones, etc.) that detects thepresence of the person. When the person speaks, the wearable electronicdevice provides the alert to the listener so the listener candistinguish between a voice originating from the software applicationand a voice originating from the room in which the listener is located.

Consider an example in which the wearable electronic device includes asensor (e.g., a camera or motion sensor) that detects gestures of a handor body of the listener. In response to detecting a hand or body motionof the listener, the wearable electronic device changes a voice of theuser from the electronically generated binaural sound to one of stereosound or mono sound. This function enables the listener to change thevoice from being provided as binaural sound to being provided as mono orstereo sound without providing a verbal command. For example, when thelistener tilts his or her head in a predetermined direction or sequence,the wearable electronic device changes the voice of the user from theelectronically generated binaural sound to one of stereo sound or monosound or changes the voice from one of mono sound or stereo sound toelectronically generated binaural sound.

The visual alert also includes generating and displaying an animatedobject that represents the source of the sound in the physicalenvironment.

Consider an example in which the listener wears a wearable electronicdevice while communicating with a user or playing a VR software game.The listener is not able to see his or her physical environment whilewearing the wearable electronic device. A person located at the physicalenvironment talks to the listener but the listener cannot discernwhether the voice originated from a person in the physical environmentor from the VR software game. The wearable electronic device includes amicrophone and voice recognition software that detect sound from theperson and recognize it as a voice in the room with the listener. Inresponse to this detection, the VR software application generates anddisplays an animated object to the listener in the VR environment whilethe user is talking to the listener. When the person stops talking, theanimated object disappears from the VR environment. This process enablesthe listener to quickly and easily discern that the voice being heardwas from a person in the physical environment and not from the VRsoftware game.

An example embodiment is thus able to detect (e.g., with a microphone,camera, or other sensor) the presence of a person or sound in a physicalenvironment of a person and provide the listener with an alert. Thealert, for example, informs the listener that a voice of a person orother sound is not originating from the VR environment but isoriginating from the physical environment of the listener. For example,the wearable electronic device detects a voice of a person not in the VRenvironment but in the physical environment. In response to making thisdetection, the wearable electronic device activates and displaysmovement of a 3D image in the VR environment in a field-of-view of thelistener to provide a visual indication to the listener that the voiceof the person does not emanate from the VR environment but does emanatefrom the physical environment of the listener.

In order to distinguish between PE sound and AR sound, exampleembodiments provide the alert as AR sound that moves with respect to ahead of the listener (e.g., moving between binaural sound and mono orstereo sounds). For example, after playing a part of the sound thatincludes audial cues necessary for external localization, the soundbecomes stereo sound, and then mixes down to two-channel monophonicsound.

In an example embodiment, an audio alert moves from one SLP internalizedby the listener to a second SLP externalized away from the listeneralong a trajectory. The listener can perceive that the sound moves fromhis head to the second SLP. For example, an AR sound of a voice of atelephone call plays to a listener at a SLP with coordinates (R, θ, ϕ).The listener may be confused by a sudden externalized voice, so thevoice is played at the internalized SLP briefly, and the listeneradjusts to the fact that he is receiving a phone call voice. Then theSLP azimuth and elevation are gradually changed to θ and ϕ. For example,the electronic system renders the voice to coordinate (0, 0, 0) (e.g.,by using, or extrapolating downward from, HRTFs with small values or rsuch as a near-field pair, or by reducing a two-channel voice to onechannel, or by not convolving a voice source), and then fetches anotherpair of HRTFs with a smallest available r coordinate to continueprocessing the voice. As the listener continues with the phone call, thedistance coordinate r is gradually increased to R, corresponding HRTFsare fetched or interpolated for the incrementing values of r, and theSLP is moved along this trajectory from inside the head to outside thehead. By the time the distance coordinate reaches R, the listener isable to externalize the voice at the final SLP. The externalized voiceis introduced in a comfortable way that does not startle the listener.Playing electronic binaural sound in this manner serves as a method todistinguish AR sound from PE sound.

Another way to distinguish AR sound from PE sound is to provide thelistener with both internal localization sound (e.g., stereo or monosound) and external localization sound or AR sound. Introducing the ARsound with an internalized SLP and then adjusting to an external SLPenables a listener to know that the sound is an AR sound.

After the caller and the listener terminate the telephone call, thelistener hears a sound play at an external SLP where he recently heardthe voice of the caller. The sound transforms to a mono sound as thedistance coordinate of the SLP is gradually reduced from R to valuesapproaching zero. A sound that transforms from an external SLP to aninternal SLP is understood to be an AR sound because it is rare to hearPE sounds in this manner.

A telephone call is commonly a known interaction with a party notphysically present. Therefore, an example embodiment graduallyintroduces the SLP into the listener's space and gradually removes it.So the listener experiences a sound starting in his head, emerging fromhis head to the SLP, and then moving back into his head along a matchingpath. The listener remains confidently correct that the sound is not PEsound. As an AR sound, it both begins and ends in his head. The movingof the SLP can be accompanied by a fade-in or fade-out of the sound.

An example embodiment provides the listener with trans-dimensional soundto assist the listener in distinguishing between AR sound and PE sound.Trans-dimensional sound can be localized both externally (3D as ARsound) and internally (2D as stereo or mono sound). Such a sound canassure the listener both that the sound did not originate in thelistener's physical environment, and that the listener's AR system iscapable of delivering localized binaural sound. Additionally, atrans-dimensional sound can be convolved in real-time from alistener-generated sound, ensuring that the sound heard by the listeneroriginates from his electronic system and is not played to him from anoutside source. This type of sound also serves to indicate that theelectronic system is active.

For example, a listener perceives a two-channel sound change frominternalized sound with no external localization to externalized soundwith external localization. At the beginning, the sound includesinsufficient human audial cues to produce external localization, such asa monophonic sound with both the left and right channels delivering onesignal. As the sound continues to play, human audial cues areintroduced. The left and right signals diverge and the sound widens tostereo introducing differences in the channels (e.g. panning a soundfrom the left side of the soundstage to the right side, or a dialoguebetween characters positioned on opposite sides of the soundstage). Thestereo source can widen further and can include a segment whereindependent left and right sources are unmixed and isolated from eachother providing an opportunity for a listener to confirm the operationof both channels. Gradually the sound externalizes into one or moresound localization points (SLPs) of AR sound. The listener hears the ARsound localized in his or her audio space.

A listener can designate a binaural “ringtone” with a transforming soundas an incoming call and/or disconnection alert. For example, Aliceallows remote callers to designate a SLP for their voice in her spacewithout informing Alice of the position of the SLP that they select.Alice does not want to be surprised by a localization so she chooses toidentify her incoming binaural calls with the binaural sound of aringing bell. A resulting incoming call alert that Alice hears is aninternalized ringing bell transforming to an externalized ringing bellat the SLP designated by the caller. After the call, another similaralert (e.g. a chime played in reverse) transforms from externalizing atthe point of the voice of the caller, to a position inside the head ofAlice. The perception that an AR sound originates from the position of alistener and ends at the position of the listener can provide a“psychological closure” of the call. In real world conversations, peopledo not suddenly appear at a location, speak, and then vanish. Instead,people come from somewhere, speak, and exit to somewhere. A listener canfind the localization pattern less confusing than seemingly hearing aninvisible person or sound at an SLP suddenly play at a proximatelocation or suddenly become silent without an exit. A comfortablealternative is to render the AR sound at the position of a listener'selectronic device, transform the externalization to a target SLP, andthen return the SLP to the position of the electronic device. Bothexamples provide the listener with a predictable location for AR sounds(in the head or at the electronic device), and a way to distinguish thesound as an AR sound and not a PE sound.

Another way to notify a listener is with an audio alert that includesbinaural sound at multiple SLPs. For example, each SLP can be a musicalnote that when played together form a musical chord familiar to thelistener. Each note of the chord can represent a particular function ofthe electronic system and the playing of the note can indicate that acertain electronic system is operating. For example, a listener of theelectronic system expecting the familiar chord will know upon hearingthe sound of the report if a note is missing. The missing note indicatesthat a function of the electronic system needs attention.

Trans-dimensional sound can also assist the listener in distinguishingbetween AR sound and PE sound. For example, a trans-dimensional sound isplayed upon power-up, login, the donning of earphones, following theinitiation of an electronic call such as a binaural call, in the interimprior to call connection, or when an audio alert or report is requested.For example, a trans-dimensional sound can be the alert for an incomingcall, such as a telephone call providing electronic binaural sound.

The position and/or movement of the binaural sound through one or moreSLPs can communicate further diagnostic or other data to the listener.As an example, consider as an indication that the electronic system hasan activated or “powered-up” SLS capable of providing binaural sound:the sound of the artificial sound effect of the swish of air seeminglyproduced by a first or open hand in a karate film. Such a sound canindicate the operational status of both an AR system and a gesturesensing system by producing the swish sound localized to the gesturinghand of a listener. For example, a listener wishes to check, test, orconfirm that his audio augmented reality (AAR) system or SLS isactivated, or that one or more SLPs are currently able to produce sound.The listener queries the operational status by performing a rapid armmovement. A swish sound from a SLP near his arm indicates to thelistener that he is able to perceive non-PE sound at this time.

The listener indicates to the electronic system that he wishes toconfirm the system's readiness and/or state of activation of the SLS,for example by performing a gesture, or with a voice command. Inresponse to the indication, the system plays a prearranged sound thatbegins with a lower degree of perceivable localization and ends with ahigher degree of perceivable localization. For example, the system firstprovides the sound in mono, then switches the sound to stereo, thenswitches the sound to binaural sound at a predetermined SLP away fromthe listener. If the listener perceives the end of the prearranged soundat one or more SLPs then he or she knows that the SLS is currentlyactive.

If the listener perceives the end of the prearranged sound withoutlocalization, (internalized within his head, at no particular SLP, ordoes not perceive the prearranged sound at all), he or she can suspect aproblem with the SLS or other part of the electronic system.

In an example embodiment, a listener can request the system to provide areport so the listener can determine whether the audio portion of theelectronic system is properly functioning. The listener can request thereport in unconventional ways.

For example, the listener produces a humming sound (i.e., a wordlesstone produced with the mouth opened or closed) to request a report fromthe system. A hum such as a hum of an approximate prearranged frequencycan be a sufficiently unique sound, independent of language, that can beidentified by the listener's electronic system and rarely produce afalse positive request for a report. A listener can produce a hum soundwithout opening the mouth, at a low volume, and a hum is more discreetthan a vocal command since a hum does not cause proximate people tofalsely believe the listener is speaking. The request from the listenermay also be in the form of a discreet natural movement. One appropriategesture is a head tilt. The head tilt, head turn, or head cock is acommon reflex gesture performed by humans when attempting to moreclosely discern the distance of a sound source directly ahead, behind,overhead, or below. A tilt gesture can be readily detected by the headorientation determiner 1177 discussed herein (e.g., using gyroscopicsensors in the earphones or other sensors).

An example embodiment allows a listener to designate a single SLP inquestion. By touching or activating the SLP he can distinguish that thelocalization is not PE sound.

A listener can designate a SLP by “touching” the SLP. A sensor orelectronic device in the listener's environment is able to know theposition of his hand with respect to an SLP. When the listener's handcoincides with the location of the SLP (in the experience of thelistener “touching” the location or the sound), this event can cause theSLP to indicate to the listener whether it is a PE sound or AR sound. Ifthe SLP is known by the electronic system to be coincident with a nearbyobject, the electronic system is afforded additional ways of knowingthat the SLP is being touched, such as visual confirmation of a hand atthe location of the object using a camera in communication with thesystem.

Consider an example in which Alice hears a mosquito at a certaincoordinate (r, θ, ϕ), and she does not know if a mosquito is in her roomor if her AR system is localizing the sound of the mosquito. Alicereaches out toward the sound. When her hand intersects with the location(r, θ, ϕ) to touch the mosquito, the sound is adjusted to a fuzzy orscratchy or static mosquito sound, as if her hand has corrupted themosquito sound. The unnaturally modified sound indicates to Alice thatthe sound is an AR sound, not a real sound, and therefore a mosquito isnot in her room.

Consider another example in which Alice receives a doll as a gift andplaces it on her desk. She hears singing coming from the doll and shedoes not know if it is a singing doll or if the sound of singing isaugmenting the sound she hears externalized at the location of the doll.She touches the doll. Upon touching or nearly touching the doll shehears her own prerecorded voice say, “it's an illusion.” As otherexamples, she hears the click of a wine glass at the position of thedoll, or she hears the sound of singing internalized during moments whenher hand is at the doll. These example audible reports confirm for Alicethat the doll cannot sing.

The head tilt gesture can also select a single SLP to query or adjust.The electronic system can interpret the direction of the head tilt, nod,cock, or gaze as the direction toward the target SLP. Further, thesystem can trigger the selected SLP to, for example, indicate to thelistener that the SLP represents an AR sound.

An example embodiment can inform the listener that a selected sound isAR sound by switching the sound to an internalized sound for theduration of the selection. For example, the listener designates acertain sound to be internalized for a brief duration (e.g., he or sheselects or clicks a location of a localization while wearing a HMD). Thelistener can naturally infer that a failure of his or her command tointernalize the sound indicates that the sound is PE sound originatingin the room. The listener knows that, consistent with PE sound, thesound does not internalize. This method of distinguishing a sound allowsthe listener to continue listening to the sound without interruption ofthe content of the sound.

Other methods that can indicate that the sound originates from an AR SLPare to mute, unmute, pause or resume the playing of an audio stream, orother action. The event of touching or dragging a SLP can also cause itto be rendered on a visual display, or rendered differently on a visualdisplay. These indications can aid in moving the SLP and also aid indistinguishing an AR SLP from a PE sound. For example, while wearing aWED or smart glasses that include earphones, Alice hears a doll singingand nods toward the doll. A gesture sensor in her wearable electronicdevice detects that the nearest SLP in the direction she nodded is anSLP at the doll playing a singing sound. In response to the nod gesture,the electronic system pauses the singing sound. Alternatively, ratherthan a nod gesture, Alice cocks or tilts her head 15° to the side whilelooking at the doll as though she is wondering about the doll. In fact,she is wondering about the doll and the gesture suits the use of thegesture. A gesture sensor registers the infrequent but discreet tilt andtriggers a gaze detector to sample Alice's gaze vector. The gaze vectoris found to pass through the coordinates at the SLP of the doll andAlice hears the doll laugh at its position, and then words, “Oh don'tstare . . . ” from matching polar coordinates but from half the distancecoordinate. Then Alice hears, “ . . . It's just me . . . ” spoken nearher left ear, and then the word, “Dolly!” whispered at a location insideher head. This relaxes Alice because the trans-dimensional audio reportreveals to Alice the true nature of the silent inanimate doll as onethat does not produce PE sound.

One or more of a set of SLPs can be commanded to play sound in order toestablish that a certain location relative to the listener can produceAR sound. In situations when a listener has an electronic device withouta visual display, a software application can execute to cause SLPs (orsubsets of SLPs such as active, inactive, silent, selected, recentlycreated, owned, not owned, SLPs that played sound less than a certainnumber of minutes in the past, SLPs with a distance coordinate notgreater than a certain r, etc.) to audibly enumerate. For example, eachSLP can “count off” one after another in turn, automatically, orone-by-one with each audible enumeration triggered by the listenerconfirming a next step. The execution of the enumeration can betriggered by events such as triggered by a listener or other user with agesture or key press or other command. A listener can command a nextstep forward in the enumeration, or a step backward in the enumeration.The sound played in the enumeration can be one sample sound, adjusted toconvolve at each SLP, so the listener can hear how the sample sounddiffers at each SLP. The enumerations sound can be a different soundplayed at each SLP such as ordered consecutive numbers (e.g. “SLP one,”“SLP two,” “SLP 3”). Each SLP may be labeled or relabeled. Theenumeration sound played to identify each SLP can be a verbal recitationof the label of the SLP. Additionally, the enumerations can be played atone point in time or one after another in turn. If an electronic deviceof the listener has head-tracking or gaze tracking hardware andsoftware, a software application can be instructed to cause a chime toplay at each SLP that is included within the bounds of a listener'sgaze. In this way, a listener can pan and scan an environment to listenfor otherwise recently silent and undetected SLPs. SLPs can be selectedand caused to make a continuous or repeating sound in a similar way to abeacon until deselected or canceled or for a period of time. Playing aselection of many SLPs can help a listener identify unknown SLPs.

In order to distinguish AR sound from PE sound, the electronic systemcan execute together with images on a visual display. For example, thedisplay can highlight the location of each active or silent SLP, andthis visual indication shows the listener that sound localizations notcorresponding to a PE source of sound. For example, consider a listeneramidst a number of SLPs, some corresponding to physical objects in theroom, some in space with no visual correspondence, some stationary andsome in motion. A listener may be unable to distinguish or recall SLPlocations when the SLP is not providing sound. A listener can execute anapplication on a handheld portable electronic device (HPED) or otherelectronic device in communication with a camera and display screen inorder to display or expose the SLPs within the field of view of thecamera lens. For example, a software application can overlay imagesrepresenting SLPs in the environment of the listener. These images aredisplayed in perspective according to each SLP's position relative tophysical objects, walls, ceilings, etc. The display screen can functionas a window to enable a listener to view SLPs or visualize SLPcoordinates that otherwise are invisible. The HPED can be waved andpanned across an environment to search for otherwise silent andundetectable SLPs. Alternatively the listener can see the SLPs renderedas images while wearing a HMD or OHMD.

A SLP not explicitly designated to be visible can be visually renderedtemporarily while it has focus, or is selected, or while it is beingmoved. The SLP can disappear from the display after being moved orunselected.

A listener can determine AR sound from PE sound in other ways as well.For example, AR sound can be presented in a distinct way from PE sound.Alternatively, PE sound can be emphasized in contrast to AR sound. Forexample, AR sound can be highlighted or distinguished by default if alistener is roaming in public, sleeping, driving, if AR sound is rarelyplayed, etc. Whereas, PE sound can be highlighted or accented by defaultif a listener is aware of the convention, such as an immersive gameplayer who remains in VR for hours. The PE sound that disturbs him canbe highlighted, rather than highlighting the game sound for hours.

Sound can be “watermarked” as a method of highlighting the sound toassist a listener in distinguishing sound. A listener can designate theelectronic system to include with each AR sound a “watermark” such asone or more of unique recognizable audio tweaks such as a particularpitch, frequency, timbre, reverberation, word pace, syllabic tempo, playrate, resonance, color, spectral profile, or other qualities of a soundand their combinations. Another type of watermark may be imprinted on,convolved with, or played together with the AR sound such as abackground sound.

Background sound can be played during AR sound. For example, abackground sound can be a white noise sound that a listener can ignore,but that is distinct in its absence. Consider an example backgroundsound of distant crashing waves or breeze that is included when an ARsound is played, so that a listener can distinguish the AR sound from PEsound by the sound of distant crashing waves.

A background sound can be played during the playing of an AR sound andalso during AR silence, and can be muted when a PE sound is played. Thismethod solves two additional problems by providing the listener with twoadditional pieces of information. The background sound emphasizes thatsound perceived without background sound is PE sound. The contrast ofthe background sound ceasing provides the listener with an audial cue inorder to distinguish that the sound played at the moment when thebackground sound is muted is a PE sound. So PE sound is positivelydistinguished. The background sound informs the listener that the ARsystem is active and that the listener is not blind to AR sound (ARblind). In other words, the listener gets confirmation that he or she isable to hear AR sound should AR sound be designated to play.

Alternatively, a background sound can be played during PE sounds, or,during PE sound and PE silence but muted during AR sound. One example PEbackground sound is a “room tone” with few distinct impulses responses(IRs) but carrying the IR color of a space. As a specific example,consider as a PE background sound the amplified sound captured bymic-thru. This example background sound assures the listener that the PEsystem is operating and that the listener is not PE blind (i.e., thelistener is able to hear PE sound should it occur). A sudden PE sound orimpulse can be detected and the volume reduced prior to playing throughthe earphones so that that a default safe amplification of the PE soundcan be restored.

Alternatively, one background sound can be played during PE sound, andanother background sound can be played during AR sound. For example, anelectronic system assigns the white noise sound of distant rain to PEbackground sound because it is raining, and a white noise backgroundsound of wind to AR sound.

A family of one type of background sound can be played during PE sound,and another set of related background sounds can be played for AR sound.Consider an example in which one tone is played during periods of ARsilence and when an AR sound is louder than an PE sound, and anothertone is played during periods of PE silence, and when PE sound is louderthan a concurrent AR sound. In this example, both tones are playedduring periods when both AR and PE systems are active but quiet.Consider further that the two different tones when played together causea distinct sound so that the absence of one is detected by a listener,and this allows the listener to passively monitor the active states ofthe PE and AR systems. In other words, if the listener does not hear thedistinctive dual-tone sound during a period of quietness then he is madeaware that the AR system or PE system is not functioning.

Consider an example in which one tone is the anti-phase wave of theother tone, so that when played together the listener hears no tone dueto destructive interference, but when one tone is missing the listenerhears a tone. Alternatively, one tone plays during PE sound, and theanti-phase tone plays during AR sound. The resulting effect is that thetones are heard when an PE sound is playing and a AR sound is notplaying, or vice-versa, but the tones are not heard if both an PE and ARsound is playing. These and other background sound schemes both help alistener to distinguish PE sound from AR sound, and/or to alert alistener to a condition of PE blindness and/or AR blindness.

A listener may instruct the system to provide AR sounds with one or moreaudial “tags” such as fade-ins and/or fade-outs, a tick or tone appendedand/or prepended to each AR sound or sound phrase. The tags can alsooccur intermittently or at regular intervals.

Consider an example in which a listener wears earphones that enable thelistener to hear both electronic binaural sound from the earphones andPE sounds as naturally occurring sound that passes through theearphones. The listener would be unable to distinguish the naturalsounds from electronically generated binaural sounds. The earphones,however, provide a “ping” sound as an alert sound at an external SLP orin an external localization zone before the electronic binaural soundlocalizes to the SLP or zone. When the listener hears the ping, he orshe knows that the next sound will be an electronic binaural sound. Theping thus provides the listener with an audio warning or audio noticethat the sound is an electronic binaural sound.

The alert sound can be selected and presented in a way that helps toprevent the listener from being startled. For example, instead ofplaying a ping, the electronic system plays a soft muffled sound thatcan alert the listener without a sudden impulse that may surprise thelistener. Two different listener-preferred sounds can introduce an ARsound or PE sound respectively. For example, following a period of nomic-thru signal in the earphones, the electronic system enters an idlemode and stops playing sound to a listener. Later, a sudden sound in thelistener's space occurs when his sister speaks to him. The speech of thesister is captured in real-time from the listener's mics but stored inmemory and delayed by three seconds. A soft alert sound plays to thelistener at a low volume that increases gradually such as over aduration of three seconds. The soft alert sound is followed by the voiceof the sister and the listener is not startled. The duration of thephrase of the sister's speech is six seconds, but due to thethree-second gentle “wake-up” sound, the listener hears the firstsyllable of the speech three seconds later than it was spoken. Theelectronic system plays the six seconds of speech at a quickerartificial rate (e.g., without changing the pitch) that compresses thesix seconds of speech into four seconds. The listener is not startled,and he is able to distinguish the sound as PE sound. He is able torespond to the voice with a delay of +1 second. As the conversationcontinues, the PE system is no longer in an idle state and the listenerhears the rest of the speech in real-time.

Consider further this example of the listener wearing earphones. Thelistener does not like to hear the “ping” sound and prefers to hearanother sound instead. The listener selects a different sound from hissound listener preferences, and this newly selected sound plays as thealert or notice that the sound is an electronic binaural sound.

The alert sound indicates that an electronic binaural sound can occurbefore the electronic binaural sound plays or while the electronicbinaural sound plays. For example, if electronic binaural sound playsfor an extended period of time, the listener may forget that the soundplaying is actually electronic binaural sound. The system can set thewarning or notice sound to play at predetermined intervals (such as 30seconds, one minute, two minute, five minute intervals, etc.). Alistener can establish these intervals. A computer program (e.g., anintelligent user agent or IUA) or a manufacturer can set theseintervals.

Zones can also distinguish PE sound from AR sound. In one exampleembodiment, a listener is apprised of a sound being an electronicbinaural sound based on where the sound externally localizes withrespect to the listener.

Certain sounds are assigned to certain zones or certain SLPs. A soundappearing in one zone or a certain SLP indicates to the listener thatthe sound is actually an electronic binaural sound. For example, alistener designates a zone above his head for certain AR sounds, such asincoming voice messages. When the listener localizes the voice of avoice message above his head, he knows that the voice does not come froma person in the room above his head.

A listener can distinguish PE sound from AR sound according to thevolume or loudness of the sound. For example, a default, maximum,minimum, average or rolling average volume delivered by the mic-thrusystem can be decreased so the listener experiences a quieterenvironment, or the amplification can be increased (e.g. the generalfunction of a hearing aid for the hearing impaired). A listener, IUA, orother software program can adjust a ratio or mix of mic-thru signals toAR signals at 50:50, 0:100, 100:0, or a ratio in between such as 80:20.A listener, IUA, or other software program can also adjust amplificationindependently for mic-thru and AR signals. For example, a listeneradjusts AR volume to a maximum loudness of “2” as marked on the loudnessadjustment interface. Thereafter the listener can identity sound heperceives at a loudness greater than “2” as PE sound. The PE:AR soundmix can be inverted or toggled. For example, a listener sets PE:ARloudness at 1:9 while he plays a game. When he hears his mother callingfrom downstairs in his house (at a low volume), he triggers the mix toinvert to 9:1 so he can hear his mother's voice louder. He still hearsthe sounds in the game at a lower volume. Toggling the ratio allows alistener to quickly change auditory focus between AR sound and PE sound.

A loudness inversion or other change in sound can be triggered in manyways. Some examples include but are not limited to: a listener“double-click's” his teeth in a closed mouth and the sound or impulse isdetected by a sensor such as the listener's mics, a listener clencheshis jaw, contracting a muscle causing a bulge or motion near the ear tobe detected by a sensor at the earphones, a listener wiggles his earsand a motion from the contraction of the auricular superior and/orauricular posterior is detected by a sensor at the earphones, a gesture,a manual switch on the HPED.

The electronic system can determine to invert or adjust the volumes andtrigger the change without direction from the listener. For example, asudden loud PE noise can be shielded from the listener and reduced involume or an urgent AR alert can be played louder. A binaural cue cantrigger a change in volume such as the detection that a listener isgiving attention to a particular PE sound. For example, a listenerplaying a computer game has a PE:AR ratio set at 20:80. His motherapproaches him in his room but the volume of her voice is low (asdictated by the ratio selected by the listener), so the listener turnsto face his mother. Because the listener adjusted PE sound to a lowerrelative volume, the lower volume of his mother's voice assists thelistener in distinguishing the voice as a PE sound. As the listenerfaces his mother who is standing at 0° azimuth, the electronic systemdetects that the left and right signals have a matching ITD and ILD. Theelectronic system determines that the listener is giving attention tothe PE sound because the PE sound is at or near 0° azimuth. Inaccordance with this determination, the electronic system increases thePE volume and/or reduces the AR volume, such as by toggling theinversion of the ratio or PE:AR balance.

FIG. 5 shows an electronic system 500 that provides a listener 510 withan alert to distinguish between physical environment sound andelectronic binaural sound.

The listener 510 is at a first geographic location, sits at a desk 520,and speaks with a proximate person 540 in the room. The listener 510also speaks with another person 530 in a remote location over one ormore networks 560. The listener 510 hears the voice 542 (drawn as anexample waveform within a “speech balloon” coming out of the head of theproximate person) of the proximate person 540 from the location of thehead of the person 540 as the person 540 speaks.

Microphones 512 included in a wearable electronic device 514 worn by thelistener 510 capture the voice of the proximate person 540 and the voiceof the listener 510. The voice 542 passes through the microphones 512and wearable electronic device 514 to the ears of the listener 510.

One or more processors process and/or convolve a voice 532 of the remoteperson 530 so this voice is provided to the listener 510 as electronicbinaural sound that externally localizes. The voice can localize to thelistener to empty space or at a physical object. By way of example, thelistener 510 hears the voice 532 of the remote person 530 as binauralsound localized to the position of a cup 522 on the desk 520. Sound doesnot emanate from the cup 522, but the sound of the voice 532 of theremote person 530 is convolved by a processor in the electronic system500 such that the listener 510 localizes the voice 532 at the positionof the cup 522. Hence the listener 510 is shown as localizing two voicesin the room. A voice 542 of the proximate person 540 is sound beinggenerated in the physical environment shared by the listener and theproximate person. Another voice 532 (drawn as an example waveform withina “speech balloon” coming out of the cup 522) is electronicallygenerated binaural sound delivered via a network 560 and not emanatingfrom a person in the room.

Listener 510 localizes the two voices in front of him or her fromsimilar locations. That is the SLP of voice 542 and the SLP of voice 532appear close to each other from the point of view of the listener 510.However, the listener 510 can distinguish the electronically generatedbinaural sound of the voice 532 from the voice 542 occurring in the roomdue to one or more audio alerts 534 and 536 (drawn as example impulsewaveforms) played along with the convolved voice 532.

An example embodiment convolves audio alert 534, a short impulse ortone, to the SLP of the voice 532 prior to playing the voice 532 of theremote person 530. This improves the experience of the listener 510 byproviding a warning or alert to the listener 510 regarding the SLP ofthe incoming voice 532. Alternatively an example embodiment plays audioalert 536 following, during, instead of, or in addition to playing theprepended audio alert 534.

Consider this example wherein the speech 532 is a sentence or a phraseof speech of the remote person 530, and the audio alert 536 is appendedto the phrase, following the phrase, as shown. For example, when theremote person 530 stops talking momentarily, the example embodimentconvolves the audio alert 536 with a same HRTF pair executed to localizethe speech to the cup 522. Alternatively, the audio alert is processedto localize another way (e.g., at a zone designated for audio alerts,inside the head of the listener, or in accordance with another exampleembodiment discussed herein). An example embodiment plays an audio alertthat beeps in mono sound to the listener following each phrase of speechthat the listener localizes externally.

Consider this example wherein the time between audio alert 534 and audioalert 536 is a set duration such as five seconds, ten seconds, thirtyseconds, a minute, etc.

This improves the experience of the listener 510 by preventing thelistener from attributing the words or sounds of the remote person 530to the proximate person 540, and vice-versa.

Remote person 530 sitting in a chair 594 at a desk 592 with a laptopcomputer 534 wears an OHMD 562 providing augmented reality images andsound so that remote person 530 sees an image or avatar 516 and hearsconvolved speech 518 of listener 510 as though proximate to the desk592.

An example embodiment plays an audio alert 519 each time there is apause or lull in the inbound voice from listener 510. The voice 518 fromlistener 510 (indicated for ease of illustration as a speech bubble thatemanates from image location 516) is convolved to a SLP coincident ornear to AR image 516. The audio alert appended to the speech 518 is notconvolved to the external location 516 and is instead processed tolocalize internally to remote person 530 at SLP 566.

The AR image 516 is shown as a dashed outline in the FIG. 5 in order todistinguish the AR image from physically present people 550 and 530shown with unbroken or non-dashed lines. Although the drawingillustrates the AR image with dashed lines, the AR image or avatar mayappear to the wearer of the OHMD 532 with a high degree of realism orindistinguishable from a human being that is physically present such asperson 550. This example embodiment improves the understanding of person530 because the person 530 hears frequent audio alerts during theconversation with listener 510 that serve to both inform andintermittently remind person 530 that the AR image 516 is an image andnot a real person.

Remote person 530 also speaks with the person 550 who is present in theenvironment together with person 530. An example embodiment captures thespeech 552 of person 550 with microphones included with OHMD 562. Thisspeech can be provided to the person 530 as pass-thru speech or speechthat is not altered. Alternatively, the OHMD 562 can alter the speech oradd to the speech in accordance with an example embodiment. When thisspeech passes-thru, the person 530 localizes the speech 552 at thelocation of the head of person 550.

Consider another example wherein the speech 552 (which is physicalenvironment sound) is processed or altered with the OHMD. For example, abackground sound 554 is added to, mixed with, convolved with, or playedtogether with the speech 552. This background sound is a lower volumethan the speech, has a constant nonintrusive waveform, starts before thespeech 552, and continues after a phrase or after a pause of the speech552. Consider a similar example wherein an audio alert that is abackground sound is played to distinguish the speech of remote speakersalternatively to distinguishing speakers or sound sources that arephysically present.

FIGS. 6A-6H show an electronic system with fields-of-view of a listener610 wearing a WED or OHMD during a telephone call or other communicationwith a user.

FIG. 6A is a third-person point-of-view of the listener 610 facing aperson 620 together in a room 600. The listener 610 is engaged in aphone call executing on the OHMD 612 worn by the listener. For example,an OHMD is a wearable display such as electronic glasses or anotherwearable electronic device having the capability of reflecting projectedimages and providing them as AR. For example, the OHMD projects an ARimage of a caller or user and allows the listener to see the physicalenvironment including proximate people in a room. The OHMD permits thelistener to see and hear things in the physical environment, such as theperson 620 in the room 600. The OHMD is also capable of modifying oraugmenting images in a field-of-view 614 of the listener (thefield-of-view 614 is shown as a dashed-lined ellipse). The OHMD alsoincludes headphones or speakers that deliver binaural sound and permitthe listener 610 to externally localize sound to positions in the room600. For example, a voice of a caller externally localizes to a soundlocalization point 632.

FIGS. 6B-6H show the field-of-view that the listener sees through theOHMD at various times, including things in the physical room 600, suchas person 620 and images augmenting the field-of-view, such as an image630C of a caller. Some FIGS. 6B-6H also include illustrations indicatingsounds such as speech.

The caller is not physically present in the room. As such, a caller isnot visible in the room 600 and not shown in FIG. 6A because FIG. 6A isa third-person point-of-view of the room and not an illustration of aview as seen by the listener 610. FIGS. 6B-6H, however, illustrate whatthe listener 610 sees in his field-of-view while wearing the OHMD 612.In the field-of-view (FOV) of FIG. 6C the listener does see an image630C of a caller in the room and also sees the person 620 in the room.In FIG. 6C the OHMD 612 augments the FOV as seen by the listener 610 toinclude the image of the caller 630C in the room.

Consider an example embodiment in which an image of a caller does notappear to the listener 610 except during the time that a caller isspeaking or sending sound. For example, listener 610 engages in atelephone call with a caller and while a person 620 is in the room 600.Before the caller speaks, the listener 610 sees a field-of-view such asshown in FIG. 6B in which an image representing the caller does notappear. In FIG. 6B OHMD 612 is not displaying an image of a caller. Whenthe caller does speak or emit a sound 632C (for the sake of illustrationthe sound is shown in the figure as a waveform in a “speech bubble” butthe sound or speech is not visible in this example), then the OHMD 612includes an image 630C of the caller. As the caller continues to speak,the listener continues to see the image 630C of the caller.

When the caller terminates the call, stops speaking, or pauses speaking,an example embodiment stops or pauses displaying the image 630C of thecaller. This results in the listener seeing the FOV of FIG. 6B. Thedisplay of the image 630C of the caller alternates between being shownand not shown in accordance with the caller speaking or not speakingrespectively. The listener 610 sees his FOV alternating between FIGS. 6Band 6C accordingly, as the caller stops and starts speaking.

Consider an example in which the image 630D of a caller presented by theOHMD 612 to augment the FOV of the listener 610 is not a 3D image butinstead a 2D image 630D, such as a smiling circle. The 2D image isrendered such that the listener can localize the position of the 2Dimage in the 3D environment (e.g., with visual cues such as shadows,reflections, and scaling) when the caller sends voice or a sound 632D.

Consider an example in which an image 630E representing a caller doesnot disappear when the caller is not speaking, but instead changes inappearance, such as by changing a color or brightness. For example, anOHMD presents to a listener the FOV of FIG. 6D in which the listenersees image 630D representing the caller while hearing the voice of thecaller 632D. When the caller stops talking, the listener sees the FOV ofFIG. 6E in which the image 630E representing the caller persists beingdisplayed but is changed in appearance, such as having a dashed outline,a lower brightness, or a different color. If and when the caller speaksagain, the image representing the caller on the display is updated(e.g., to a solid line, a greater brightness, a different color) toindicate to the listener 610 that the voice localizing at or near theimage 630D is an AR voice and not the voice of person 620 or otherphysically present person.

An example embodiment uses colored lights to distinguish electronicbinaural sound from sound originating in the physical environment forthe listener. Consider an example where a blue light, LED, image,background, or highlight is activated to indicate that a sound is beingplayed that is not originating in the physical environment of alistener.

FIGS. 6F and 6G show FOVs at times in which a remote caller is speakingand a proximate person 620 is speaking, respectively. An exampleembodiment includes a blue visual alert 650F shown in FIG. 6F to beactivated, indicating that electronically generated binaural sound (inthis case sound 632F) is being played. The FOV also includes a greenvisual alert 652F that is not activated. FIG. 6G shows the FOV withdeactivated blue alert 650G indicating that a binaural voice (e.g.,sound 632F) is not actively playing. The activation of a green alert652G indicates that the caller is presently listening or that amicrophone or virtual microphone is monitoring the caller and/or thelistener 610. Alternatively, the activation of alert 652G is triggeredwhen microphones included in the OHMD 612 detect voice or other sound inthe physical environment in order to indicate that the physicallyproximate person 620 is presently speaking (e.g., the voice 622G thatthe listener is localizing to its point of origin at the head of theperson 620). Consider an alternative example wherein the colored lightsthat indicate an origination of sound represent eyes, face, or body of acaller, image of a caller, or avatar.

FIG. 6H shows another FOV seen by the listener 610 in which an image oricon exhibits some animation in order to indicate to the listener thatAR sound is being played (in this case the AR sound is the voice of thecaller 632H). For example, a 2D image pulses, a wireframe image changesposition, or looping sequence of images appear to the listener asmoving, rotating, hopping, color-shifting, throbbing, or otherwiseanimating. 660H is an animation of a cube spinning in place andindicates that, while spinning, electronically generated binaural soundis being played to the listener. A dashed arrow indicates the directionof rotation of the cube icon. The direction is changeable. Also, thetype of animation is changeable. For example, a colored light or LED cananimate smoothly in gradations or in steps from blue to green to blue.When the caller stops or pauses speaking, the animation 660H continues,or stops, or slows, or changes. For example, the cube appears to spinfor the duration of the telephone call including during the time whenthe caller is not speaking. When the caller is not speaking the cubespins more slowly or changes color. At the termination of the telephonecall the cube stops spinning.

FIGS. 7A-7J show an electronic system with fields-of-view of a listenerwearing a WED or HMD during a telephone call or other communication witha user. The size, shape, resolution, and type of field-of-view (FOV)provided by a HMD vary. An example FOV is shown is a dashed-linedellipse 714.

The HMD includes headphones or speakers that deliver electronic binauralsound and permit the listener to externally localize sound to positionsproximate to him or her, such as a location of a voice of a calleroriginating from a location that is one meter or more away from a headof the listener. The HMD also has microphones at the ears of thelistener that can capture sound from the physical environment andpresent this PE sound to the listener in a pass-through mode, withvariable amplification, or with some modification of the sound capturedfrom the physical environment. FIGS. 7A-7J show the FOV that thelistener sees via the HMD at various times. To aid in discussion, somefigures also include illustrations indicating sounds such as speech.

Consider an example embodiment in which an image of a caller does notappear to the listener except during the time that a caller is speakingor at a time when an electronic device of the caller is sending sound.FIGS. 7A and 7B show two FOVs of the listener engaged in a VR telephonecall with callers Alice (being shown as 720A-720J) and Bob (being shownas 730A-730J). Before Alice and Bob speak, the listener sees the FOV ofFIG. 7A in which the images representing Alice 720A and Bob 730A are ina state of lower visibility such as faint, transparent, translucent, lowresolution, or invisible. The lower visibility state is indicated asdashed outlines of the images that represent the callers 720A and 730A.When Bob speaks his voice 732B is convolved to the location of his imageat 730B. The voice 732B may be illustrated on the display of the HMD inthe FOV to the listener to inform the listener that Bob is speaking(e.g., as a waveform and/or text such as in a “speech bubble”). For easeof illustration, the speech is shown as waveforms in some figures.

When Bob speaks the image of Bob changes to become visible, morevisible, highlighted, or accented such as by changing a level oftransparency or translucency, changing a color, or changing in anotherway. The more visible state is indicated in FIG. 7B as a continuousoutline. As Bob continues to speak, the listener continues to see theimage or avatar of Bob 730B. When Bob stops or pauses speaking then theimage representing Bob returns to the less visible, less highlighted, orless accented state represented in the FOV of FIG. 7A as image 730A.

FIG. 7C shows a FOV with both callers speaking and so the imagesrepresenting Alice 720C and Bob 730C are therefore being visuallyrepresented with a higher visibility. The listener sees the FOV of FIG.7D at a moment in which Alice is speaking so the image representingAlice 720D is more visible or highlighted than the image representingBob 730D who is not speaking. The increased visibility of the imagerepresenting a current speaker improves the experience of the listenerby informing the listener whom or which character or caller is beingheard.

The FOVs of FIGS. 7E and 7F show respectively a moment when Bob isspeaking, and then pauses speaking. In this example, the imagerepresenting Bob 730E is an icon, 2D image, or other image that mayinclude or not include a likeness of Bob. It is not necessary for animage representing a caller to be a 3D model or 3D image. A 3D image ora flat image can be displayed so as to visually localize in the 3D VRspace of the listener by using shading, shadows, scaling, and othervisual rendering techniques. When Bob stops speaking and the listener nolonger hears the voice of Bob 732E, an example embodiment adjusts theimage representing Bob from an image that is more visible 730E to animage that is less visible 730F, not highlighted, or not visible. Alicedoes not start or stop speaking during the times shown in FIGS. 7E-7F,so images representing Alice 720E-720F are not triggered to change withrespect to visibility.

An example embodiment uses colored lights to distinguish a caller thatis speaking, or a voice or sound that is convolved to localize in the VRenvironment or a voice or sound that is captured from the physical roomof the listener. Consider an example where a blue light, LED, image,background, or highlight is activated to indicate that a sound is beingplayed that is not originating in the physical environment of alistener. FIGS. 7G and 7H show FOVs that distinguish active voices. Anexample embodiment includes an activated blue visual alert 750G at thehead of an image representing Bob 730G, distinguishing Bob as thespeaker of the voice 732G.

FIG. 7H shows the FOV with deactivated blue alert 752H that isillustrated as an ellipse under the image representing Bob 730Hindicating that a voice of Bob is not actively playing. The activatedalert 750H around the feet of the image representing Alice 720Hindicates that Alice is presently speaking (e.g., the voice 722H islocalizing at 720H). Alternatively, the activated alert 750H indicatesthat Alice is presently listening or that a microphone or virtualmicrophone is monitoring Alice and/or the listener. The ellipses orother shapes can appear to be shadows, spotlight beams, or glowing floortiles. The ellipses or other shapes surround or highlight the image thatrepresents the caller, on the floor or ground beneath the image, orbehind the image.

FIG. 7I shows another FOV of the listener in which an image or iconexhibits animation in order to indicate to the listener which caller isspeaking. For example, the image of Bob 730I is seen in the FOV tovibrate (as indicated in FIG. 7I with vibration lines). The animation ofthe image 730I indicates that, while vibrating or animating, theelectronically generated binaural sound 7321 is being localized to thelistener at approximately the location of the animated image 730I.

FIG. 7I also shows lights, LEDs, or highlights as spheres over the headsof the images representing Alice 720I and Bob 730I. These spheresrendered at or over the images representing Alice and Bob can be anyassigned different colors and the significance of the color and theactivation and position of the lights or highlights are changeable.

FIG. 7J is a FOV with a voice of Chuck 772J indicated to localize froman image of Chuck 770J. The listener sees an image of Alice 720J who isnot speaking and an image of Bob 730J who is speaking. The listener doesnot see the physical environment of the room that he or she occupies. Aperson Chuck enters the physical room occupied by the listener andspeaks. Microphones of an HMD at the ears of the listener capturebinaurally the sound of the voice of Chuck 772J. An example embodimentcalculates an interaural time difference (ITD) of the sound of thecaptured voice of Chuck. Upon determining the ITD the embodiment furtherdetermines an azimuth angle relative to the facing direction of thelistener and corresponding to the ITD and renders an image of a person770J at the azimuth angle. In this example, a reduced visibility shownas a transparent dashed-outlined figure indicates to the listener thatthe person speaking the sound 772J is physically proximate to thelistener who is wearing the HMD, and indicates an approximate directiontoward the person.

One problem with wearing headphones that capture and amplify physicalenvironment sound from the physical environment as well as supplyelectronic binaural sound is that a listener may need to quickly switchor alternate between focusing on the sound from the physical environmentdelivered by the headphones, to focusing on other sound delivered by thedevice or headphones (e.g., electronic binaural sound, music, phonecalls).

One or more example embodiments solve this problem and provide a quickand convenient way for a listener to change between listening toelectronic binaural sound and listening to physical environment sound.

FIG. 8 is a method that detects an action of a portable electronicdevice and changes sound in response to detection of the action.

Block 800 states detect an action of a portable electronic device.

The actions include, but are not limited to, one or more of rotating theportable electronic device, moving of the portable electronic device(e.g., shaking the portable electronic device or moving it through theair in a predetermined way), gripping or holding the portable electronicdevice (e.g., grabbing the portable electronic device with a hand),activity of a person (e.g., sensing when the person is walking orrunning or sitting), releasing the portable electronic device (e.g.,releasing the portable electronic device from a hand), covering a sensorof the portable electronic device (e.g., covering or darkening a lens ofa camera), detecting a face of a person (e.g., detecting with facialrecognition software the presence or proximity of a person), detectingabsences of a face of a person (e.g., detecting with facial recognitionsoftware an absence of a face of a person), detecting or sensing light,detecting or sensing darkness, detecting or sensing presence of a personor hand (e.g., with a sensor), detecting or sensing an identity orbiometric of a person (e.g., detecting a fingerprint or thumbprint ofthe person, identifying a person by iris image, retina scan, ear form,or another biometric), detecting a change in an electrical power sourceof a PED (e.g., changing between battery-supplied power and anothersource of power), detecting a change in audio output configuring of aPED (e.g., changing from between sound being output from speaker andsound being output from headphones, detecting the an event of headphonesbeing plugged-in or unplugged, coupled to the PED or decoupled, poweredon or off), or another action discussed herein.

By way of example, one or more sensors in the portable electronic devicedetects when the action occurs. For instance, these sensors include, butare not limited to, a camera, a gyroscope, an accelerometer, amagnetometer, a compass, an optical or capacitive scanner, a display, aproximity sensor, a light sensor, a pedometer, a fingerprint sensor, oranother sensor.

Block 810 states change, in response to detecting the action, soundbeing provided to a listener with that sound being physical environmentsound and/or electronic generated binaural sound provided with thewearable electronic device.

The portable electronic device changes or switches sound being providedto the listener in response to detecting the action. Consider an examplein which a three-axes accelerometer and/or gyroscope in the portableelectronic device senses rotation of the portable electronic device. Inresponse to detecting the rotation, the portable electronic device takesan action with regard to the sound. These actions include changing avolume or loudness of AR sound relative to PE sound, changing acharacteristic of the PE sound or AR sound, changing or switching ARsound or PE sound (1) from being binaural sound to being mono sound orstereo sound or (2) from being mono sound or stereo sound to beingbinaural sound, toggling the output of the headphones between AR soundand PE sound. Other actions include, but are not limited to, muting thesound, lowering the volume, raising the volume, stopping the sound,ending or terminating a telephone call, placing a telephone call onhold, joining another call, joining another virtual auditory space,muting or pausing or changing a particular sound type or input source,or performing another action.

In an example embodiment, toggling or switching between providing ARsound at a higher volume or loudness than PE sound, and providing PEsound at a higher volume or loudness than AR sound occurs when theportable electronic device (e.g., a WED with or in communication withheadphones or earphones) detects a gesture of the listener.

Consider an example in which smart earphones include sensors, such as aninertial motion unit (IMU) with an accelerometer, magnetometer, andgyroscope. The IMU senses or detects an amount and/or speed of rotationof the earphones as worn by the listener. When the amount of rotationand/or speed of rotation of the head reaches a predetermined threshold,the smart earphones execute one or more of the actions (e.g., reducesthe volume of the AR sound and/or increases the amplification of the PEsound).

For example, a listener is playing PE sound louder than AR sound inorder to monitor the surroundings. When the listener cocks his or herhead (e.g., 20° roll of the head toward the left shoulder), the exampleembodiment makes the AR sound louder than the PE sound. Tilting of thehead of the listener thus provides a convenient way to change betweenfocusing on sound of AR or VR or music, and sound occurring in the room.Example embodiments are not limited to the threshold value or amount oftwenty degrees (20°) since other threshold values or amounts can bedesignated to trigger a change between PE sound and AR sound.

Consider an example in which proximity sensors on left and rightearphones detect the presence or position of a hand. A hand gesture thatcovers a left or right side of an earphone triggers a muting of the ARsound, while a hand gesture covering the contralateral earphone triggersa muting of the PE sound. As another example, a hand gesture thattouches or covers a left (or right) earphone triggers a reduction of theamplification of the PE sound that is being captured and/or increasesthe volume of the other sound being delivered by the earphones. Agesture that is a cupping of the hand behind the left (or right)earphone triggers an increase in the amplification of the PE soundand/or a lowering of the volume or loudness of the AR sound. Thisimproves the experience of the listener since a gesture of coveringone's ear is a common action to lessen environmental noise, and agesture of cupping a hand behind a pinnae is a common or useful gesturewhen a listener desires to amplify or focus on the sound coming from aparticular direction in the environment.

Consider an example in which the action of changing relative soundvolumes of AR sound and PE sound occurs when the electronic devicedetects a change in orientation of the electronic device such as withrespect to a face and/or head of the user. When the change reaches orexceeds a threshold value, then execute the change. The change inorientation can occur in one of several ways. First, the orientation ofthe head and/or body of the user changes with respect to the electronicdevice while the electronic device does not move. For instance, a userrotates his head or moves with respect to a stationary camera, facingsensor (e.g., front-facing sensor, rear-facing sensor), or other sensor.Second, the orientation of the electronic device changes with respect tothe user while the user does not move. For instance, a user holds asmartphone in his or her hand while the camera captures an image of theface and executes facial recognition and distance determination. Theuser rotates the smartphone so the camera no longer captures the face ofthe user. Third, both the user and the electronic device move to changethe orientation of the user with respect to the electronic device. Forinstance, the user holds the smartphone in his hand and simultaneouslyrotates his head and the hand holding the smartphone.

Consider an example in which the action of changing relative volumes ofthe binaural sounds is triggered when a WED detects rotation of aparticular rotational or angular speed of the WED. For example, alistener wears an OHMD and rotates his or her head slowly and no changeis triggered. When the listener rotates the head quickly, a change istriggered. The change is triggered when the rotation occurs within apredetermined time or crosses another threshold, such as a predeterminednumber of revolutions per second or radians per second. By way ofexample, a change in the sound is triggered when a quarter rotation orninety degrees of rotation occurs within a range of 0.1 seconds-0.5seconds. Consider an example in which a listener wearing smart glasseswith earphones is in a telephone call and has adjusted the volume of thevoices of the phone call to be louder than the voices of other people inthe room where the listener sits. The listener is approached by someonein the room who needs help, so the listener rotates his head to triggerthe PE sound to be louder than the phone call and AR sounds. Afterattending to the person, the listener rotates the head again to togglethe AR sound as the primary sound with the higher volume.

Consider an example in which a listener holds a smartphone in front ofhis face while talking to a friend. The listener hears the voice of thefriend as binaural sound that localizes to an image on the display ofthe smartphone. To switch the voice from being provided in binauralsound that externally localizes to the smartphone to being provided inmono or stereo sound that localizes inside a head of the listener, thelistener performs one of the actions discussed herein. As one example,the smartphone gives priority to PE sound when a camera in thesmartphone ceases or fails to detect a face of the listener. Forinstance, prioritize AR sound only while the camera detects the face ofthe listener. Change to prioritizing PE sound when the camera no longerdetects the face of the listener. As another example, the smartphonetoggles the prioritization of AR:PE sound when the camera or anothersensor detects darkness. For instance, give priority or weight to PEsound if the camera or sensor does not detect a certain level of light.Change the focus to AR sound when the camera is activated (e.g., thelistener places the smartphone on the table, exposing the display orcamera; the listener removes the smartphone from a pocket or purse,etc.).

Consider an example in which an electronic device captures an image of aperson with a camera. The electronic device executes a softwareapplication to detect a face and perform facial recognition. During theperiod of time that the camera detects the face of the person, theelectronic device reduces the volume of sound captured at the ears ofthe person. When the camera no longer detects the face of the person,then the electronic device performs an action (such as toggling therelative volumes of the AR and PE sound from/to 80:20 to/from 20:80).

Facial detection and/or facial recognition enables a person to togglequickly back and forth between concentrating on manufactured binauralsound and paying attention to the events nearby. For example, during atelephone call or while playing a software game, a listener holds a HPED(e.g., holds a smartphone in his or her hand) or wears a WED (e.g.,wears an electronic watch). A camera in the HPED or WED monitors theface of the listener. When the listener desires to change toggle thesound, the listener rotates the HPED or WED so the camera ceases tocapture or detect the face of the listener, or capture somethingdifferent. When the listener desires to change back to the prior soundbalance, the listener rotates the HPED or WED so that the cameracaptures or detects the face of the listener, or captures something new.

Instead of or in addition to rotating the HPED or WED, an exampleembodiment allows the listener to make the mic-thru sound louder or lessloud compared to the VR phone call sound by moving his or her head. Acamera in the HPED or WED monitors the face of the listener. The HPED orWED changes the sound when the HPED or WED detects a change in headorientation or a change in gaze of the listener (e.g., the listenerlooks away from the camera or display or rotates his or her head by apredetermined amount). For instance, the electronic device changes fromaccentuating local sounds to accentuating VR voices or vice-versa whenone of the following occurs: the listener stops gazing or looking at thedisplay, the listener turns his or her head away from the display, thecamera no longer detects the face of the listener, the camera detects a“full face” view, a side profile, a “three-quarter” view, or anotherview between a “full face” view and a profile of a face of the listener,the camera detects a top of the head of the listener, and the cameradetects that the eyes of the listener are closed for a predeterminedamount of time.

Consider an example in which a listener talks to another person during atelephone call while holding a smartphone or other HPED. The listenerhears the voice of the other person as binaural sound that localizes atthe HPED. The HPED changes the relative energy levels of the AR soundvs. the PE sound upon detecting an action from the user, such asdetecting an incoming phone call, detecting a non-vocal mouth or bodysound impulse (e.g., impulse from clapping, impulse from biting orclicking the upper and lower teeth together), detecting a manual volumeadjustment, detecting a hand gesture, detecting a facial gesture or headgesture, detecting a voice command or vocal energy change (e.g., ashout) or a vocal frequency (e.g., a hum of a certain note), ordetecting another action. Detection of one of these actions enables thelistener to change quickly between focusing on auditory events that arehappening around his or her body and voices, music or other sound thatis inbound from another location or virtual environment.

Changing an AR or PE loudness or relative volume can also occur inresponse to detecting or sensing a change in distance of a listener froman object, such as the electronic device. For example, a camera orfacing sensor in a HPED tracks an image or orientation of a person orface of a person during a video call. The person hears the voice of theother person during the video call in binaural sound and also hears thePE sound of the room. When the person moves a predetermined distancefrom the HPED display the HPED automatically increases the volume of thevoice so that the listener can focus on the content of the spoken wordswithout the benefit of seeing the accompanying video of the caller thatincludes additional informational cues such as facial expression, headand hand gestures, and lip movements. For instance, change the relativesound volumes when the person moves more than one meter away from apresent position or from the HPED, more than 1.5 meters away, more than2.0 meters away, etc. A camera or sensor captures an image ororientation of the head of the person, and the distance of the person orhead from the HPED is determined based on a size of the face and/or bodyimage captured or sensed with the camera or sensor.

One way to distinguish between electronically generated binaural soundand physical environment sound is to provide the sound to the listenerin different formats, such as mono sound, stereo sound, and binauralsound. When the listener hears sound in two or more of these formats,the listener becomes aware that an audio alert is being provided. Thealert notifies the listener that the sound the listener is hearing orwill hear is electronically generated binaural sound or physicalenvironment sound.

The audio alert can be a separate sound from the sound being provided tothe listener, such as a separate beep, tone, noise, or other sound toalert the listener. Alternatively, the audio alert can actually be thesound itself without a separate sound as the audio alert. For example,the sound being provided to the listener is convolved or processed intotwo or more formats of mono sound, stereo sound, and binaural sound.Natural or physical environment sound does not appear to listeners withsuch format changes so the listener becomes aware that the sound he orshe is hearing is electronic binaural sound.

For example, consider an incoming voice from a caller to a listenerAlice that is twelve seconds long and that says, “Hello Alice, my voicebegins as though in your head but as I continue, my voice moves awayfrom you until you eventually hear my voice way out to here, two metersaway.” An example embodiment processes and plays the sound as onecontinuous twelve second sound, but having five sections as follows:

Section 1-0:00 seconds to 0:02 seconds—play as monophonic sound.

Section 2-0:02 seconds to 0:04 seconds—play as stereo sound,left-panned.

Section 3-0:04 seconds to 0:06 seconds—play as stereo sound,right-panned.

Section 4-0:06 seconds to 0:09 seconds—play as binaural sound convolvedto a distance on one meter.

Section 5-0:09 seconds to 0:12 seconds—play as binaural sound convolvedto a distance of two meters.

As a result of the processing, Alice hears the twelve-second sentence asthe voice of the caller. The first few words she hears localizeinternally as mono sound; she hears the next few words toward the left,the next few words toward the right. As the playing of the twelve-secondvoice continues, she soon externalizes the voice of the caller. If thevocal greeting began as suddenly localizing to two meters, Alice may bestartled, as well as unsure of the origin of the voice. By processingthe beginning of voice telecommunication in this way, an exampleembodiment allows a listener to begin receiving the voice of an incomingcaller without first selecting a SLP and with an assurance that thevoice does not come from a proximate person. This improves theexperience of the listener by allowing an incoming caller to select aSLP without startling the listener, and saving time while establishingthe call since the listener does not need to allow incoming binauralsound calls on a case-by-case basis.

Consider an example where the twelve-second incoming voice is processedper the five sections above, and also includes smooth transitionsbetween the sections. For example, between section 1 and section 2, thestereo width begins with a narrow separation. Between section 2 andsection 3, the stereo pan slides gradually from the left, through acenter balance, to the right, between section 4 and section 5 the voiceis convolved to 1.3 m, then 1.6. Between section 3 and section 4,individual characteristics of the sounds or waveform samples areinterpolated.

FIG. 9 shows a method that enables a listener 900 to distinguish betweenelectronically generated binaural sound and physical environment soundin accordance with an example embodiment.

The sound being provided to the listener 900 switches or changes formatsof mono sound, stereo sound, and binaural sound; and this switching orchanging signifies to the listener that the sound is electronic binauralsound and not physical environment sound.

Switching or changing of the sound is shown along a line 910 thatsignifies where the listener localizes the sound. Initially, the soundstarts as mono sound and localizes inside the head 920 of the listener.The sound then changes to stereo sound and localizes inside the head 920of the listener. This change between mono sound and stereo sound isshown with the curved or S-shaped line 910 inside the head of thelistener 900.

Line 910 proceeds to exit a right ear of the listener 900 and stops at afinal sound localization point (SLP) 930. This line illustrates thesound changing from stereo sound (which is localized internally) tobinaural sound or binaural audio (which is localized externally). Thelistener will hear the sound inside the head and then outside his or herright ear and moving away from his or her head along the line 910 untilthe sound stops moving to the SLP 930. Movement of the sound signifiesor alerts the listener that the sound he or she is hearing is actuallyelectronic binaural sound and not physical environment sound.

Consider an example of the listener talking to a user while the listenerwears an OHMD. When the user first speaks to the listener, the listenerwould not be able to distinguish whether the voice of the user isoriginating from a VR application executing with the OHMD or from aperson physically located near the listener. Voices from both sourcessound identical to the listener, and both voices externally localize asbinaural sound. In order to assist the listener in distinguishingbetween these two sources of sound, the OHMD switches or changes theformat of the voice of the user. For example, the voice of the userstarts as mono sound, then changes to stereo sound, then changes tobinaural sound. Natural human voice cannot perform such changes. So, thelistener knows that the voice of the user is electronic binaural soundfrom the VR application of the OHMD.

FIG. 10 is a computer system or electronic system 1000 in accordancewith an example embodiment. The computer system includes one or more ofa portable electronic device or PED 1002, one or more computers orelectronic devices (such as one or more servers) 1004, and storage ormemory 1008 in communication over one or more networks 1010.

The portable electronic device 1002 includes one or more components ofcomputer readable medium (CRM) or memory 1020 (such as cache memory andmemory storing instructions to execute one or more example embodiments),a display 1022, a processing unit 1024 (such as one or more processors,microprocessors, and/or microcontrollers), one or more interfaces 1026(such as a network interface, a graphical user interface, a naturallanguage user interface, a natural user interface, a phone controlinterface, a reality user interface, a kinetic user interface, atouchless user interface, an augmented reality user interface, and/or aninterface that combines reality and virtuality), a sound localizationsystem (SLS) 1028, head tracking 1030, a digital signal processor (DSP)1032, and one or more sensors 1034 (such as a camera, proximity sensor,or other sensor discussed herein).

The PED 1002 communicates with wired or wireless headphones or earphones1003 that include speakers 1040 and/or other electronics (such asmicrophones 1042).

The storage 1008 includes one or more of memory or databases that storeone or more of audio files, sound information, sound localizationinformation, audio input, SLPs and/or zones, software applications, userprofiles and/or user preferences (such as user preferences for SLPlocations and sound localization preferences), impulse responses andtransfer functions (such as HRTFs, HRIRs, BRIRs, and RIRs), and otherinformation discussed herein.

The network 1010 includes one or more of a cellular network, a publicswitch telephone network, the Internet, a local area network (LAN), awide area network (WAN), a metropolitan area network (MAN), a personalarea network (PAN), home area network (HAM), and other public and/orprivate networks. Additionally, the electronic devices need notcommunicate with each other through a network. As one example,electronic devices couple together via one or more wires, such as adirect wired-connection. As another example, electronic devicescommunicate directly through a wireless protocol, such as Bluetooth,near field communication (NFC), or other wireless communicationprotocol.

Electronic device 1004 (shown by way of example as a server) includesone or more components of computer readable medium (CRM) or memory 1060(including cache memory), a processing unit 1064 (such as one or moreprocessors, microprocessors, and/or microcontrollers), a soundlocalization system 1066, and an audio or sound convolver 1068.

The electronic device 1004 communicates with the PED 1002 and withstorage or memory that stores sound localization information (SLI) 1080,such as transfer functions and/or impulse responses (e.g., HRTFs, HRIRs,BRIRs, etc. for multiple users) and other information discussed herein.Alternatively or additionally, the transfer functions and/or impulseresponses and other SLI are stored in memory 1020 or another location,such as storage 1008.

FIG. 11 is a computer system or electronic system in accordance with anexample embodiment. The computer system 1100 includes one or more of aportable electronic device 1102, a server 1104, a portable electronicdevice 1108, and a display 1105 in communication with each other overone or more networks 1112.

Portable electronic device 1102 includes one or more components ofcomputer readable medium (CRM) or memory 1120 (including cache memory),one or more displays 1122, a processor or processing unit 1124 (such asone or more microprocessors and/or microcontrollers), one or moresensors 1126 (such as a micro-electro-mechanical systems sensor, aproximity sensor, a biometric sensor, an optical sensor, aradio-frequency identification sensor, a global positioning satellite(GPS) sensor, a solid state compass, a gyroscope, a magnetometer, and/oran accelerometer), earphones with speakers 1128, sound localizationinformation (SLI) 1130, an intelligent user agent (IUA) and/orintelligent personal assistant (IPA) 1132, sound hardware 1134, a SLPselector 1138, and one or more microphones or mics 1140.

Server 1104 includes computer readable medium (CRM) or memory 1150, aprocessor or processing unit 1152, and a DSP 1154 and/or other hardwareto convolve audio in accordance with an example embodiment.

Portable electronic device 1108 includes computer readable medium (CRM)or memory 1160 (including cache memory), one or more displays 1162, aprocessor or processing unit 1164, one or more interfaces 1166 (such asinterfaces discussed herein in FIG. 10 ), sound localization information1168 (e.g., stored in memory), a an alert generator 1170, userpreferences 1172, one or more digital signal processors (DSP) 1174, oneor more of speakers and/or microphones 1176, head tracking and/or headorientation determiner 1177, a compass 1178, inertial sensors 1179 (suchas an accelerometer, a gyroscope, and/or a magnetometer), and a camera1180.

The alert generator 1170 generates an audio and/or visual alert toassist a listener in distinguishing between binaural electronic soundand physical environment sound. The alert generator and the soundlocalization point (SLP) selector include specialized hardware and/orsoftware to execute example embodiments, such as selecting alerts,selecting a desired SLP for where binaural sound will localize to auser, and/or selecting coordinate locations of HRTFs being executed toconvolve the sound.

A sound localization system (SLS), alert generator, and SLP selectorinclude one or more of a processor, core, chip, microprocessor,controller, memory, specialized hardware, and specialized software toexecute one or more example embodiments (including one or more methodsdiscussed herein and/or blocks discussed in a method). By way ofexample, the hardware includes a customized integrated circuit (IC) orcustomized system-on-chip (SoC) to select, assign, and/or designate aSLP or a coordinate location for sound or convolve sound with SLI togenerate binaural sound. For instance, an application-specificintegrated circuit (ASIC) or a structured ASIC are examples of acustomized IC that is designed for a particular use, as opposed to ageneral-purpose use. Such specialized hardware also includesfield-programmable gate arrays (FPGAs) designed to execute a methoddiscussed herein and/or one or more blocks discussed herein. Forexample, FPGAs are programmed to execute selecting, assigning, and/ordesignating SLPs and coordinate locations for sound or convolving,processing, or preprocessing sound so the sound externally localizes tothe listener.

The sound localization system (SLS) performs various tasks with regardto managing, generating, interpolating, extrapolating, retrieving,storing, and selecting SLPs and coordinate locations and can function incoordination with and/or be part of the processing unit and/or DSPs orcan incorporate DSPs. The SLS can also function to execute exampleembodiments to generate audio and/or visual alerts. Other tasks include,determining coordinates of SLPs and other coordinate locations and theircorresponding HRTFs, switching and/or changing sound between binauralsound and mono sound or stereo sound, selecting SLPs and/or coordinatelocations of HRTFs for a user, selecting objects to which sound willlocalize to a user, designating a type of sound, segment of audio, orsound source, providing binaural sound to users at a SLP, prefetchingand/or preprocessing SLI, and executing one or more other blocksdiscussed herein. The sound localization system can also include a soundconvolving application that convolves and de-convolves sound accordingto one or more audio impulse responses and/or transfer functions basedon or in communication with head tracking.

In an example embodiment, the SLS calculates the line-of-sight orimaginary line from the head of the listener to an object designated asa SLP and retrieves SLI (including HRTFs) based on the location of theline. For instance, two points or locations determine a line. One pointis located at the head of the listener. Information about the headorientation of the listener can be determined from or calculated from acamera or a head tracking and/or head orientation determiner (e.g.,hardware and/or software in a head mounted display or other wearableelectronic device). A second point is located at the origin of thesound, such as the object designated as a SLP. Information about thelocation of the second point can be determined from or calculated from acamera, a sensor, tag or RFID, or an electronic device. For instance, anelectronic device calculates its position with respect to a head of thelistener using one or more of a camera, facial recognition, a MEMSsensor (e.g., a multi-axis sensor with 9 degrees of freedom), wirelessshort-range communication with another electronic device (e.g.,communication between an HPED and a wearable electronic device orelectronic device in an Internet-of-Things (IoT) network), or othermethod.

By way of example, an intelligent personal assistant or intelligent useragent is a software agent that performs tasks or services for a person,such as organizing and maintaining information (such as emails,messaging (e.g., instant messaging, mobile messaging, voice messaging,store and forward messaging), calendar events, files, to-do items,etc.), initiating telephony requests (e.g., scheduling, initiating,and/or triggering phone calls, video calls, and telepresence requestsbetween the user, IPA, other users, and other IPAs), responding toqueries, responding to search requests, information retrieval,performing specific one-time tasks (such as responding to a voiceinstruction), file request and retrieval (such as retrieving andtriggering a sound or video to play, or text or images to display),timely or passive data collection or information-gathering from personsor users (such as querying a user for information), data and voicestorage, management and recall (such as taking dictation, storing memos,managing lists), memory aid, reminding of users, performing ongoingtasks (such as schedule management and personal health or financemanagement), and providing recommendations. By way of example, thesetasks or services are based on one or more of user input, prediction,activity awareness, location awareness, an ability to access information(including user profile information and online information), userprofile information, and other data or information.

By way of example, the sound hardware includes a sound card and/or asound chip. A sound card includes one or more of a digital-to-analog(DAC) converter, an analog-to-digital (ATD) converter, a line-inconnector for an input signal from a source of sound, a line-outconnector, a hardware audio accelerator providing hardware polyphony,and one or more digital-signal-processors (DSPs). A sound chip is anintegrated circuit (also known as a “chip”) that produces sound throughdigital, analog, or mixed-mode electronics and includes electronicdevices such as one or more of an oscillator, envelope controller,sampler, filter, and amplifier. The sound hardware can be or includecustomized or specialized hardware that processes and convolves mono andstereo sound into binaural sound.

By way of example, a computer and a portable electronic device include,but are not limited to, handheld portable electronic devices (HPEDs),wearable electronic glasses, smart glasses, watches, wearable electronicdevices (WEDs) or wearables, smart earphones or hearables, voice controldevices (VCD), voice personal assistants (VPAs), network attachedstorage (NAS), printers and peripheral devices, virtual devices oremulated devices (e.g., device simulators, soft devices), cloud residentdevices, computing devices, electronic devices with cellular or mobilephone capabilities, digital cameras, desktop computers, servers,portable computers (such as tablet and notebook computers), smartphones,electronic and computer game consoles, home entertainment systems,digital audio players (DAPs) and handheld audio playing devices(example, handheld devices for downloading and playing music andvideos), appliances (including home appliances), head mounted displays(HMDs), optical head mounted displays (OHMDs), personal digitalassistants (PDAs), electronics and electronic systems in automobiles(including automobile control systems), combinations of these devices,devices with a processor or processing unit and a memory, and otherportable and non-portable electronic devices and systems (such aselectronic devices with a DSP and/or sound hardware as discussedherein).

The SLP selector and/or SLS can also execute retrieving SLI,preprocessing, predicting, and caching including, but not limited to,predicting an action of a user, predicting a location of a user,predicting motion of a user such as a gesture, a change in a headdisplacement and/or orientation, predicting a trajectory of a soundlocalization to a user, predicting an event, predicting a desire or wantof a user, predicting a query of a user (such as a query to or responsefrom an intelligent personal assistant), predicting and/or recommendinga SLP, zone, predicting a suitable or optimal HRTF set for a user, orRIR/RTF to a user, etc. Such predictions can also include predictinguser actions or requests in the future (such as a likelihood that theuser or electronic device localizes a type of sound to a particular SLPor zone). For instance, determinations by a software application,hardware, an electronic device, and/or user agent are modeled as aprediction that the user will take an action and/or desire or benefitfrom moving or muting a SLP, from delaying the playing of a sound, froma switch between binaural, mono, and stereo sounds or a change tobinaural sound (such as pausing binaural sound, muting binaural sound,selecting an object at which to localize sound, reducing or eliminatingone or more cues or spatializations or localizations of binaural sound).For example, an analysis of historical events, personal information,geographic location, and/or the user profile provides a probabilityand/or likelihood that the user will take an action (such as whether theuser prefers a particular SLP or zone as the location for where soundwill localize, prefers binaural sound or stereo, or mono sound for aparticular location, prefers a particular listening experience, or aparticular communication with another person or an intelligent personalassistant). By way of example, one or more predictive models execute topredict the probability that a user would take, determine, or desire theaction. The predictor also predicts future events unrelated to theactions of the user including, but not limited to, a prediction oftimes, locations, or identities of incoming callers or virtual soundsource requests for sound localizations to the user, a type or qualityof inbound sound, predicting a sound source or virtual sound source pathincluding a change in orientation of the sound source or virtual soundsource or SLP such as a change in a direction of source emission of theSLP.

Example embodiments are not limited to HRTFs but also include othersound transfer functions and sound impulse responses including, but notlimited to, head related impulse responses (HRIRs), room transferfunctions (RTFs), room impulse responses (RIRs), binaural room impulseresponses (BRIRs), binaural room transfer functions (BRTFs), headphonetransfer functions (HPTFs), etc.

Examples herein can take place in physical spaces, in computer renderedspaces (such as computer games or VR), in partially computer renderedspaces (AR), and in combinations thereof.

The processor unit includes a processor (such as a central processingunit, CPU, microprocessor, microcontrollers, field programmable gatearrays (FPGA), application-specific integrated circuits (ASIC), etc.)for controlling the overall operation of memory (such as random accessmemory (RAM) for temporary data storage, read-only memory (ROM) forpermanent data storage, and firmware). The processing unit and DSPcommunicate with each other and memory and perform operations and tasksthat implement one or more blocks of the flow diagrams discussed herein.The memory, for example, stores applications, data, programs, algorithms(including software to implement or assist in implementing exampleembodiments) and other data.

Consider an example embodiment in which the SLS includes an integratedcircuit FPGA that is specifically customized, designed, configured, orwired to execute one or more blocks discussed herein. For example, theFPGA includes one or more programmable logic blocks that are wiredtogether or configured to execute combinational functions for the SLS(e.g., changing between binaural sound and mono sound upon detectingrotation of the HPED or detecting another action discussed herein).

Consider an example in which the SLS includes an integrated circuit orASIC that is specifically customized, designed, or configured to executeone or more blocks discussed herein. For example, the ASIC hascustomized gate arrangements for the SLS. The ASIC can also includemicroprocessors and memory blocks (such as being a SoC (system-on-chip)designed with special functionality to execute functions of the SLSand/or blocks of methods discussed herein).

Consider an example in which the SLS includes one or more integratedcircuits that are specifically customized, designed, or configured toexecute one or more blocks discussed herein. For example, the electronicdevices include a specialized or customized processor or microprocessoror semiconductor intellectual property (SIP) core or digital signalprocessor (DSP) with a hardware architecture optimized for convolvingsound and executing one or more example embodiments.

Consider an example in which the HPED includes a customized or dedicatedDSP that executes one or more blocks discussed herein (includingprocessing and/or convolving sound into binaural sound). Such a DSP hasa better power performance or power efficiency compared to ageneral-purpose microprocessor and is more suitable for a HPED, such asa smartphone, due to power consumption constraints of the HPED. The DSPcan also include a specialized hardware architecture, such as a specialor specialized memory architecture to simultaneously fetch or prefetchmultiple data and/or instructions concurrently to increase executionspeed and sound processing efficiency. By way of example, streamingsound data (such as sound data in a telephone call or software gameapplication) is processed and convolved with a specialized memoryarchitecture (such as the Harvard architecture or the Modified vonNeumann architecture). The DSP can also provide a lower-cost solutioncompared to a general-purpose microprocessor that executes digitalsignal processing and convolving algorithms. The DSP can also providefunctions as an application processor or microcontroller.

Consider an example in which a customized DSP includes one or morespecial instruction sets for multiply-accumulate operations (MACoperations), such as convolving with transfer functions and/or impulseresponses (such as HRTFs, HRIRs, BRIRs, et al.), executing Fast FourierTransforms (FFTs), executing finite impulse response (FIR) filtering,and executing instructions to increase parallelism.

Consider an example in which the DSP includes the SLP selector. Forexample, the SLP selector and/or the DSP are integrated onto a singleintegrated circuit die or integrated onto multiple dies in a single chippackage to expedite binaural sound processing.

Consider another example in which HRTFs (such as a custom or personalset of HRTFs created for a certain user or users, or other transferfunctions or impulse responses) are stored or cached in the DSP memoryor local memory relatively close to the DSP to expedite binaural soundprocessing.

Consider an example in which a smartphone or other PED includes one ormore dedicated sound DSPs (or dedicated DSPs for sound processing, imageprocessing, and/or video processing). The DSPs execute instructions toconvolve sound and display locations of images or SLPs for the sound ona user interface of a HPED. Further, the DSPs simultaneously convolvemultiple sound sources or SLPs to a user. These sound sources or SLPscan be moving with respect to the face of the user so the DSPs convolvemultiple different sound signals and virtual sound sources with HRTFsthat are continually, continuously, or rapidly changing.

In FIGS. 10 and 11 , memory in the portable electronic devices and/orserver can store executable instructions and/or applications, such asinstructions to generate and provide alerts or execute other exampleembodiments.

As used herein, the word “about” when indicated with a number, amount,time, etc. is close or near something. By way of example, for sphericalor polar coordinates of a SLP (r, θ, ϕ), the word “about” means plus orminus (±) three degrees for θ and ϕ and plus or minus 5% for distance(r).

As used herein, “electronically generated binaural sound” or “electronicbinaural sound” or “AR sound” is sound that is processed or convolvedwith an electronic device and/or processor to externally localize asbinaural sound or binaural audio to a listener.

As used herein, “empty space” is a location that is not occupied by atangible object.

As used herein, “field-of-view” is the observable world that is seen ata given moment. Field-of-view includes what a user or camera sees in avirtual or augmented world (e.g., what the user sees while wearing a HMDor OHMD).

As used herein, “line-of-sight” is a line from an observer's eye to alocation.

As used herein, “physical environment sound” or “PE sound” is soundgenerated in a physical environment of a listener without an electronicdevice, such as a voice of a person or sound from an object dropped onthe floor. Physical environment sound also includes sound generated in aphysical environment of a listener with an electronic device when thissound is not convolved or processed with an electronic device intobinaural sound, such as sound from a honking horn of a car or TV orradio playing.

As used herein, “proximate” means near. For example, a sound thatlocalizes proximate to a listener occurs within two meters of theperson.

As used herein, “sound localization information” or “SLI” is informationthat an electronic device uses to process or convolve sound so the soundexternally localizes as binaural sound to a listener. Examples of SLIinclude head related transfer functions (HRTFs), head related impulseresponses (HRIRs), binaural room impulse responses (BRIRs), room impulseresponses (RIRs), interaural level differences (ILDs), and interauraltime differences (ITDs).

As used herein, a “sound localization point” or “SLP” is a locationwhere a listener localizes sound. A SLP can be internal (such asmonaural sound that localizes inside a head of a listener wearingheadphones or earbuds), or a SLP can be external (such as binaural soundthat externally localizes to a point or an area that is away from butproximate to the person or away from but not near the person). A SLP canbe a single point such as one defined by a single pair of HRTFs or a SLPcan be a zone or shape or volume or general area, such as a line or acylindrical volume. Further, in some instances, multiple impulseresponses or transfer functions can process or convolve sounds to aplace within the boundary of the SLP. In some instances, HRTFs necessaryto produce a particular SLP for a particular user may not have beencreated. A HRTF may not be required to provide a SLP or localize soundfor a user, such as for an internalized SLP, or a SLP may be rendered byadjusting an ITD and/or ILD or other human audial cues.

As used herein, “spherical coordinates” or “spherical coordinate system”provides a coordinate system in 3D space in which a position is givenwith three numbers: a radial distance (r) from an origin, an azimuthangle (θ) of its orthogonal projection on a reference plane that isorthogonal to the zenith direction and that passes through the origin,and an elevation or polar angle (ϕ) that is measured from the zenithdirection.

As used herein, a “telephone call,” or a “phone call” or “telephony” isa connection over a wired and/or wireless network between a callingperson or user and a called person or user. Telephone calls can uselandlines, mobile phones, satellite phones, HPEDs, voice personalassistants (VPAs), computers, and other portable and non-portableelectronic devices. Further, telephone calls can be placed through oneor more of a public switched telephone network, the internet, andvarious types of networks (such as Wide Area Networks or WANs, LocalArea Networks or LANs, Personal Area Networks or PANs, home areanetworks or HAMs, Campus Area Networks or CANs, etc.). Telephone callsinclude other types of telephony including Voice over Internet Protocol(VoIP) calls, video calls, conference calls, internet telephone calls,in-game calls, telepresence, etc.

As used herein, “three-dimensional space” or “3D space” is space inwhich three values or parameters are used to determine a position of anobject or point. For example, binaural sound can localize to locationsin 3D space around a head of a listener. 3D space can also exist invirtual reality (e.g., a user wearing a HMD can see a virtual 3D space).

As used herein, “trans-dimensional sound” is sound that includeselectronic binaural sound and at least one of stereo sound and monosound.

As used herein, a “user” or a “listener” is a person (i.e., a humanbeing). These terms can also be a software program (including an IPA orIUA), hardware (such as a processor or processing unit), an electronicdevice or a computer (such as a speaking robot or avatar shaped like ahuman with microphones or points of virtual microphones in or at itsears).

As used herein, a “video call” is a telephone call in which one or morepeople to the video call see video of the other person.

Impulse responses can be transformed into their respective transferfunctions. For example, a RIR has an equivalent transfer function of aRTF; a BRIR has an equivalent transfer function of a BRIR; and a HRIRhas an equivalent transfer function of a HRTF.

In some example embodiments, the methods illustrated herein and data andinstructions associated therewith, are stored in respective storagedevices that are implemented as computer-readable and/ormachine-readable storage media, physical or tangible media, and/ornon-transitory storage media. These storage media include differentforms of memory including semiconductor memory devices such as NANDflash non-volatile memory, DRAM, or SRAM, Erasable and ProgrammableRead-Only Memories (EPROMs), Electrically Erasable and ProgrammableRead-Only Memories (EEPROMs), solid state drives (SSD), and flashmemories; magnetic disks such as fixed and removable disks; othermagnetic media including tape; optical media such as Compact Disks (CDs)or Digital Versatile Disks (DVDs). Note that the instructions of thesoftware discussed above can be provided on computer-readable ormachine-readable storage medium, or alternatively, can be provided onmultiple computer-readable or machine-readable storage media distributedin a large system having possibly plural nodes. Such computer-readableor machine-readable medium or media is (are) considered to be part of anarticle (or article of manufacture). An article or article ofmanufacture can refer to a manufactured single component or multiplecomponents.

Blocks and/or methods discussed herein can be executed and/or made by auser, a user agent (including machine learning agents and intelligentuser agents), a software application, an electronic device, a computer,firmware, hardware, a process, a computer system, and/or an intelligentpersonal assistant. Furthermore, blocks and/or methods discussed hereincan be executed automatically with or without instruction from a user.

The methods in accordance with example embodiments are provided asexamples, and examples from one method should not be construed to limitexamples from another method. Tables and other information show exampledata and example structures; other data and other database structurescan be implemented with example embodiments. Further, methods discussedwithin different figures can be added to or exchanged with methods inother figures. Further yet, specific numerical data values (such asspecific quantities, numbers, categories, etc.) or other specificinformation should be interpreted as illustrative for discussing exampleembodiments. Such specific information is not provided to limit exampleembodiments.

What is claimed is:
 1. A method comprising: displaying, with a displayof a wearable electronic device (WED) worn on a head of a user, virtualimages; processing sounds that externally localize as binaural sound tothe user at the virtual images; detecting, with the WED, a person in aphysical environment with the user; and alerting the user that theperson originates in the physical environment and not from the virtualimages by displaying a visual alert with the display of the WED.
 2. Themethod of claim 1 further comprising: repeating the visual alert toremind the user that the person originates in the physical environment,wherein the virtual images are augmented reality (AR) images or virtualreality (VR) images.
 3. The method of claim 1 further comprising:alerting the user that the person originates in the physical environmentand not from the virtual images by providing a tactile alert to the userthat includes a vibration.
 4. The method of claim 1 further comprising:determining, with the WED, a direction of the person; and displaying thevisual alert to notify the user of the direction of the person.
 5. Themethod of claim 1 further comprising: displaying, with the WED, thevisual alert at a coordinate location on the display that corresponds toa location of where the person exists in the physical environment. 6.The method of claim 1 further comprising: continuing to display thevisual alert while the WED continues to detect the person in thephysical environment; and ceasing to display the visual alert when theWED ceases to detect the person in the physical environment.
 7. Themethod of claim 1 further comprising: alerting the user that the personoriginates in the physical environment and not from the virtual imagesby playing an audio alert to the user in response to detecting theperson in the physical environment with the WED.
 8. A method comprising:displaying, with an electronic device with a user, a virtual image;processing, with one or more processors, a voice of the virtual image sothe voice of the virtual image externally localizes as binaural sound tothe user at the virtual image; and displaying, with the electronicdevice with the user and in response to detecting a person in a physicalenvironment of the user, a visual alert that notifies the user that theperson exists in the physical environment and not from the virtualimage.
 9. The method of claim 8 further comprising: repeating the visualalert while continuing to detect the person in the physical environmentof the user.
 10. The method of claim 8 further comprising: ceasing todisplay the visual alert upon not further detecting the person in thephysical environment of the user.
 11. The method of claim 8 furthercomprising: displaying, with the electronic device and to the user, anindication that shows where the person is located in the physicalenvironment.
 12. The method of claim 8 further comprising: playing arepeating sound to provide an audio alert that notifies the user thatthe person exists in the physical environment and not from the virtualimage.
 13. The method of claim 8 further comprising: detecting theperson is speaking; and notifying the user that the person is speakingby displaying a virtual image in response to the detecting the person isspeaking.
 14. The method of claim 8 further comprising: displaying thevisual alert as a virtual image at a location where the user sees theperson in order to notify the user that the person is in the physicalenvironment.
 15. The method of claim 8 further comprising: displayingthe visual alert as a flashing light while the person is speaking tovisually alert the user when the person is speaking.
 16. A wearableelectronic device (WED) comprising: a display that displays virtualimages to a user wearing the WED; speakers that play binaural sound thatoriginates to the user from the virtual image; and one or more sensorsthat detect a person in a physical environment of the user wearing theWED, wherein the display displays a visual alert that notifies the userthat the person exists in the physical environment and not from thevirtual images.
 17. The WED of claim 16, wherein the speakers play anaudio alert in the binaural sound that notifies the user that the personexists in the physical environment and not from the virtual images. 18.The WED of claim 16, wherein the visual alert is a light that activateswhile the person is in the physical environment is talking anddeactivates when the person in the physical environment stops talking.19. The WED of claim 16, wherein the visual alert is a three-dimensional(3D) virtual image that displays at a location where the user sees theperson, and the 3D virtual image moves while the person is moving andstops moving when the person stops moving.
 20. The WED of claim 16,wherein the WED is a head mounted display (HMD) worn on a head of theuser, and the one or more sensors include a microphone in the WED.